Worked for me!!!! Thanks.

damnnn....just spent $500 at the dealership before reading this thread. Luckily I still have the old unit. Anyone know if Mazda dealerships have return policies on parts they install? :S

just a question before i start soldering random things lol, The three parts that Wingnut circled on the board, am I just putting solder on them over the old ones?

Yes... you are simply adding more solder to the joint.
No reason to remove and re-solder the connector.

alright thanks for clearing that up for me =OD

ok so im at the part where you disconnect the wiring for the headunit, iv gotten the first bottom one out after finding it had a tab to push in, now the one in the middle i cant pull the unit out far enough to see if it has a tab as well or not, or do i just yank it out?

nvm got it, now to smack myself with the soldering gun for being a dopie

Did this today with the help of a friend (because I SUCK with a Solder Iron) and it worked perfectly.

Hi folks. I have been searching to help Mother with some issues on her 05 shinka. She told me the other day that she was took the car out and did not have heat. She said she warmed the car up before leaving on her 15 miles drive. The car never had heat the entire trip. She return home later and same thing. Then she said she heard a click or something (noise of the heater system changed) and there was heat. To my knowledge this is the first incident and she did not fiddle with the knobs at all.

Could her system be related to the heater control knob failure? Should I have her do anything to help determine if this is it? Does it start out intermittant and get worse from there? Since it is the first time should I just keep and eye on it and see if it becomes more regular.

Just want to have some education before she runs off and lets the dealer over charge her for something I could have fixed.

Thanks so much!

It's easy to test the heater control knob. Turn the ignition to the on position, you don't have to turn on the car but it doesn't matter if you do. Turn the radio on, then once its on press and hold the on button don't let go, then press and hold the up scan button at the same time. The radio display will say a/c temp with a number next to it. Now turn the heater control knob all the way left to cold, the number should be 0. Now turn the knob one click at a time to the right. The number should go up by 1 for each click and stop at 16 when you get all the way to the hot side. Turning the knob back to the left should have the opposite affect. If this is not the case this DIY is for you.

VIA WINGNUT, thx again...

Easy Diagnosis:
The easiest way to verify this is to turn on the radio, press and hold the power on/off button and press and hold the scan-up button for a second (full second). The word "A/C TEMP" should appear on the left of the display and a number from 0 to 16 on the right. I suspect yours will have the number 0 (or 16 if heating only problem) displayed no matter where you turn the temperature control knob. If this is the case you could turn the temp. knob to full heat and see if it goes to 16 after pushing down or to the right on the knob.
In a working system, the number moves evenly in increments of 1, from 0 to 16 as you turn the temperature knob.

This is a great DIY! Took me and some friends about 90 minutes start to finish and everything works perfectly! Thanks to everyone that has contributed to this. And a big F You to Mazda for doing such a shotty job on the control unit.

Amazing write up was having this problem all I had to do was follow the instructions and I re soldered the unit and I had heat again!!!

Hello fellows, after installing and ipod adaptor, I know have the same problem with my heat. I will definitley fix this problem myself> THANKS :)
-one question? what exactley is the problem here, how does this happen? I am guessing that after taking my HU out it got rattled or bumped. Wouldnt the problem be internal on the knob or the copper coils (not the soldering contact on the curcuit board) i just want to be thorough before attempt this repair.
how does the soldering repair fix the problem, makes me wonder?
Anyone have comments or feed back?
thanks

It happens because there was a problem with the automated assembly process that solders the parts together. The machine probably wasn't set to a hot enough temperature for the potentiometer that controls the climate control. The continuous temperature changes result in expansion/contraction of the components and they eventually no longer make a reliable connection.
I used to do component level repair of various electronic assemblies.
Less than a month ago, I had to perform this same repair.

^^ thanks Alnielsen for the quick feedback. Looks like a non-lazy Sunday i will be taking the HU out to make this repair.

Thanks, Just did it and worked like a charm however i knew i was going to lose that 10mm bolt so i didnt bother trying to save it. Now ive noticed when taking turns the display will flicker and the controls stop working. im assuming this is due to the bolt not holding it in place so does anyone have the actual bolt size so i can get a new one.

i am in need of an AC control unit, my ac temp broke. Plus i had to stick a pen tube in the temp controller to control my ac LOL.

after seeing that i have to remove the radio somewhat (which i paid someone to do) it kinda makes me lose interest in doing it.

at least i can get cold ac if i fidget around with the pen tube, but it's not that pretty to look at

Thanks, Just did it and worked like a charm however i knew i was going to lose that 10mm bolt so i didnt bother trying to save it. Now ive noticed when taking turns the display will flicker and the controls stop working. im assuming this is due to the bolt not holding it in place so does anyone have the actual bolt size so i can get a new one.

I would say go back in and check your connections. I don't think the bolt is what's hurting you. I had display issues after doing mine and came to find out that I hadn't seated a plug on the driver's side of the radio fully. I could push on the left side of the face plate and my display would come back. As I recall, I just had to pull the radio out a few inches and I could reach that plug. Not sure what to tell you about the controls other than to re-check the connections.

I just bought my 2005 RX8 and noticed that the temperature was getting stuck. I found this thread and soldered the three areas on the panel.

IT WORKED!

Great thread. THANKS!!

Like so many others who have posted here, just finished this fix...awesome write-up, epic money saver!

Thanks a million!

-Adam

Old thread, but sub'ing so I can find it if ever needed to reference in the future.

Thank you everyone. I was able to fix mine as well although I managed to break my defrost button when disassembling everything. Don't know how I did it but it snapped off the board. I was able to super glue the button back and the button worked pressing the rubber tip into the board but after I reinstalled it didn't work. Not sure if it's fixable now and didn't feel like undoing everything again. The A/C temp knob is now correctly working. Odd that the 3 solder points didn't look damaged or worn out. I added some solder to them anyways and it fixed the problem. Thanks again not having control over the temperature was really annoying. Living without the defrost button for now is no biggie for me. I may redo it again sometime and see if I can fix the button. :dubs:

Decclan

Excellent DIY,Although I'm not driving my 8 in the winter,I just did this fix in about an hour and it works perfectly.No problems at all and $400 saved.Thanks again for the great post.

I've soldered the 3 points that is shown, and have assembled everything together, the same way I took it apart, making sure that all harnesses and plugs fit properly. However, after I turn the car on, the only thing that works on the center console is the fan.
Does anyone have an idea of what could have happened here?

(No button functions, except for hazard; When I turn the lights on, the console light's up... but again, no functions work).

I would appreciate any help that you may have to offer.

THanks,

Chad

Chad................I assuming you checked the 7.5a fuse in location number 4 in the fuse box located by the drivers side door?
Also check #2 in engine bay fuse box, and give #18 a look too.
One could assume so since you went so far as to resolder these connections you'd know about these, but you never know.

Only other thing I have to offer is play with the connectors.

I assume you also had all connectors off at the time of soldering, and the heater control out of the car?

Thank you!!! I was about to freeze my butt off all winter driving to work!!! Funny how 3 drops of solder saves you $300 bucks!!! :ylsuper:

Thanks for posting this fix.
My heater control started acting up about a year ago, and it was driving me nuts. The heater would come on randomly while driving (or shut off).
I did the fix about 3-months ago, and it's been great since.

BTW - while I had the heater control out, I also fixed my in-dash oem CD changer, that I somehow managed to jam ( I think I didn't wait long enough when inserting CD's). There was a CD wedged inside. It was also holding 4 other CD hostage.

I now have a WORKING heater and a CD changer!

Well I fixed my heater problem but now the radio is posessed! I haven't pulled it out to see if anything is loose yet. For now when I turn my AC on to 1, the radio Mutes, and unmutes when I turn the AC back to 0. And once I put my car into Drive, it starts jumping back and forth between mute and audio speeding up as I speed up. It's CRAZY!!! what did I do? I'll pull it back out n check all the connections. :mchase:

My car was built 06/03. It doesnt display the 0-16 perameter on the dash like the later ones do. Is there an alternative test for my early model before I remove the assy?
Also, how can I run the self test and recalibration? The steps outlined in this thread don't work on mine.

I have no heat ever. The dash vent for the passenger is slightly warmer so I may just have a plugged heater core, but I would like to check this as well if possible.

hey guys,

I have this same problem, and sure enough the temperature gauge number would only skip from 0 to 7 randomly.

I took apart the HU, found the circuit board and located the 3 solder pins. They aren't nearly as bad looking as some of the other pics, but wanted to get your guys' opinion.

I can clearly see a ring around the base of the pins. Question is, is this what is causing the gauge to not work properly? And the soldering procedure is to seal up any breakage in connection?

Thanks-

hey guys,

I can clearly see a ring around the base of the pins. Question is, is this what is causing the gauge to not work properly? And the soldering procedure is to seal up any breakage in connection?

Thanks-

Yep the solder will reconnect the pins to the circuit board. Quite often the ring means the joint is bad. Sometimes you can just reheat the solder but looking at the pics of the boards in this thread they all look like they could use some more fresh solder.

Time for me to try this tomorrow.

Yep the solder will reconnect the pins to the circuit board. Quite often the ring means the joint is bad. Sometimes you can just reheat the solder but looking at the pics of the boards in this thread they all look like they could use some more fresh solder.

Time for me to try this tomorrow.

Thanks Elirentz, that's what i thought as well.

However, upon further investigating the solder pins, I used a continuity tester to see if I could get a signal from the outer ring, to the tip of the solder pin. Each pin tested positive for a signal, and I've tested multiple times with same results. I probably will end resoldering just to make sure, but I wonder if there's a break in the signal somewhere else.. Maybe in the rotating piece itself. Anyone know if this is even possible?

In case anyone is interested, or having a similar problem...

The solder pins (for me) don't seem to the problem, so I think I've isolated the issue to a dirty potentiometer. I'm going to try to use a bit of Deoxit tomorrow and see if I can get it cleaned out. I'll post my results.

Supabooma, those solder joints are shot. They may be in contact just from pressure while you are testing, I know that mine would work intermittently, then only when I pushed the knob in a certain way, then not much at all. I'm not saying that you don't have any other problem, i.e. dirty pot, but what ever else you do, contact cleaner, etc., make sure you solder those joints before putting the whole mess back together. IMHO. Good luck. 2 + years of flawless heat and counting.

Supabooma, those solder joints are shot. They may be in contact just from pressure while you are testing, I know that mine would work intermittently, then only when I pushed the knob in a certain way, then not much at all. I'm not saying that you don't have any other problem, i.e. dirty pot, but what ever else you do, contact cleaner, etc., make sure you solder those joints before putting the whole mess back together. IMHO. Good luck. 2 + years of flawless heat and counting.

Thanks Wingnut. I definitely will re-solder just in case. I'll probably do that before trying to clean the pot just to see if that really was the problem.

Your guide was extremely helpful, and thanks for chiming in!

yet another happy 8 owner. to bad i didnt stumble upon this at the beggining of winter instead the end...thanks though!

Supabooma, those solder joints are shot. They may be in contact just from pressure while you are testing, I know that mine would work intermittently, then only when I pushed the knob in a certain way, then not much at all. I'm not saying that you don't have any other problem, i.e. dirty pot, but what ever else you do, contact cleaner, etc., make sure you solder those joints before putting the whole mess back together. IMHO. Good luck. 2 + years of flawless heat and counting.

Wingnut, you were right! I guess the continuity test doesn't tell the whole story. I soldered the joints (skipped cleaning the pot), and everything worked perfectly.

Thanks again!

Cheers

Thanks for the DIY!!!

Just did this today, thanks to the tips it went super smooth and was easy as pie!

now I finally dont have to tap my heater knob to change between full cold/ full hot :)

Done mine just now...
works perfectly...

the hidden bolt was pain in the a*& to find... and guess what, i lost it... anyone has an idea where can i find it? i tried to took out the carpet but its seems its not there...

my temperature gauge meter reads perfectly fine. jumping evenly from 0-16 but i have got no heater. (it's slightly warmer on the passenger side) Im too dumb to solder the electrical chips or maybe i dare not to lay my fingers on them as i would just break them =(
is there any other way to fix this issue?

my temperature gauge meter reads perfectly fine. jumping evenly from 0-16 but i have got no heater. (it's slightly warmer on the passenger side) Im too dumb to solder the electrical chips or maybe i dare not to lay my fingers on them as i would just break them =(
is there any other way to fix this issue?

well if you are seeing all of the numbers 0-16 when when turn the knob, this isn't the solution to your problem as the soldering hasn't gone bad (yet).

well if you are seeing all of the numbers 0-16 when when turn the knob, this isn't the solution to your problem as the soldering hasn't gone bad (yet).

but why is there no heat coming out? i lives in minnesota and the nights here are still kinda cold without heater.

but why is there no heat coming out? i lives in minnesota and the nights here are still kinda cold without heater.

no clue but you might want to start your own thread since this is a DIY on how to fix the bad soldering on the temperature control knob. you might get better response there.

This is strange. After I soldered my AC/Heat control back to the board and put everything back in, I realized that the radio was going crazy. Whenever I start to accelerate, the mute mode will toggle back and forth and speeds up as I speed up and the beeps eventually become one solid tone. That only happens if I have the AC turned on. If I turn it to 0, the radio works normal. Once I turn it to 1 or more, it mutes. Then if I push the rear defrost button it un-mutes, and back and forth. Same thing when I push the AC button. It's like I have to turn one button on and another one off to get it to stop muting. I even took it apart thinking maybe one of the face plate connectors was misguided on the last assembly job. Eh I don't know wth to think! Did my circuit board get zapped? I'm reconnecting it now so once I drive off I'll know if it worked. I can only test it when I'm driving. Pretty annoying.

^Take it apart and put it back together again. See if that corrects the problem.

Anyone can help? I followed this DYI and now I get this when I start the car? Can't really test if it worked or not because I can't see anything... :(

Finally did this, it's been a year I've had the car and I've finally decided to bust out the solder gun. Now everything heat related works. Now I just have to fix my cd changer, don't know how but it's jammed up.

Anyone can help? I followed this DYI and now I get this when I start the car? Can't really test if it worked or not because I can't see anything... :(

i'd take everything apart and make sure the connections are good and snug, especially the display cable.

Saved me about $500 from the dealer. This DIY is awesome. :D

i'd take everything apart and make sure the connections are good and snug, especially the display cable.

Just did, and it's still the same, somehow there are even less lines now...

but the soldering did fix my temperature control, but now I got no display... not sure if I wanted this tradeoff =(

How are you getting the head unit itself out. I got the hidden Bronze bolt out, and took the two inside screws out that attach to the head unit, but the unit itself is not coming out, even a half inch.

I can't grab it from the top, but I have been grabbing it from the bottom, it is not budging, but it is bending. I feel like if I really yank on it, I am going to crack something.

It seems like the tabs holding the unit in are stuck. Any tips on clicking the tabs, the trim between the unit and the car is so tight on the sides I cannot even stick a credit card in between. Or should I be looking for something else causing this?

I just noticed that my car was stuck on cold, the connection seems to be loose or something, i can push the button and the a/c number will change but as soon as i take my hand off of it, the number goes back to zero. I still have a warranty with Mazda so i'm going to take it in and see if they'll fix it.

How are you getting the head unit itself out. I got the hidden Bronze bolt out, and took the two inside screws out that attach to the head unit, but the unit itself is not coming out, even a half inch.



You have to give it a little yank on one side first while holding the other side for stability, see if this youtube helps? shows at the last couple seconds.
http://www.youtube.com/watch?v=sG77cRRaWPM

[QUOTE=zeddy;3949513]You have to give it a little yank on one side first while holding the other side for stability, see if this youtube helps? shows at the last couple seconds.

Thanks, that helped, got it out pretty quickly after I was able to move my fingers under the right side, pop it out, and then pop the left side out.

I did it yesterday and the heater is working perfectly. (it was stuck at either 0 or 16, it would change if i dial but takes about half a minute). Thanks!!

Just some note, as the guy in the first page said, it would help if you remove the 4 screws and remove the metal bracket blocking your access to the annoying bolt. Also I broke the bezel between the faceplate and the radio. So be careful when you are pulling the radio out. Try to grab the radio instead of the faceplate..you should be able to reach the lower metal bar of the radio if you have long fingers...if not, cross your fingers..

also the hold power button + hold scan up trick does not work on my car. I don't know why... the screen would light up every letters/graphics it has...like a light bulb check. Maybe I did some wrong?

On my car stereo panel I do not have a scan up button, what I have instead is 3 button's TA, PTY and AF. When I hold the power button and the TA button (your scan up button) I do not get A/C Temp instead I get FAN and Temp. When I turn the fan knob up I get an arrow going to the right and when i turn it down I get an arrow going to the left and if i leave it i just get a dash line beside the FAN. The same goes for the temp button. Does anyone else have this same configiration as me? BTW my car is a UK (Europe) 2004 model with fully automatic Air con

Never got an answer huh ? I'm in the same boat . Guess I should just do the suggested soldering and see what happens

Ok - pulled it all apart only to find the circuit board is vastly different for JDM models . The temp control pot is totally different . I re-soldered the pot connections to the board but found that did nothing .
So i went with plan B . Shoved a hose up the core and that did the trick !

You have to give it a little yank on one side first while holding the other side for stability, see if this youtube helps? shows at the last couple seconds.
http://www.youtube.com/watch?v=sG77cRRaWPM


Nice... Wonder if there is a socket behind the 04-08 models to plug in a sound wire input...

To check using the scan/power button...do you have to disconnect the connector to the a/c amplifier? In the repair manual it says to, but not sure which plug i have to disconnect and getting either of them out is a tight squeeze.

To check using the scan/power button...do you have to disconnect the connector to the a/c amplifier? In the repair manual it says to, but not sure which plug i have to disconnect and getting either of them out is a tight squeeze.

You don't have to disconnect anything. Just hit both buttons while the car is on.

fixed the knob and it is now functioning as it should. I did find the real problem...the linkage between the air mix actuator arm and the motor that controls it broke off. The long bolt is still fine, just the plastic piece that it connects to on the end of the actuator arm. Don't even know what something like that is called? I'm gonna try and find a wrecked 8 and yank it out of there, unless someone has one?

For anyone who is having trouble finding the bolt: There is a small wedge shaped gap in the plastic. If you shine a flashlight through it and look around, the mysterious bolt will appear. Also you can go straight at it with a long ratchet extension. It will put your ratchet pretty much right under the steering column. I used the electrical tape trick mentioned in the threads to prevent losing the bolt into oblivion. Much thanks to all who contributed to this thread that saved me hundreds!

Im gonna try to fix this next weekend...... Just thought id ask is there a thread on here that has the rx8's in order of manufacture date? iv'e searched but didn't find anything... ive got an rx8 made in june of 03 and would like to know how early she is. :)

Thanks to the OP for gathering all the information :bowdown:. I did this repair tonight (among others), and in places where the factory service manual was a bit vague I was able to refer to the article listed to clear things up. Needless to say the repair went very well. Thanks again.

Fixed it! however i had a bot trickier time...... one of the previous owners had glued the control knobs on. lol however from the pics given i could tell where the bad joints were so I just melted thru the plastic back, cleaned up the melted plastic with a dremel and hit the connections thru my "port hole".
And I had no problems with the hidden bolt..... after breaking it loose i simply reached my arm up thru and took it the rest of the way out with my fingers...... no losing it. I did however loose my 10mm socket when it popped off and fell somewhere.

Another happy customer. Thanks again for a well documented fix.

Has any found the right bolt to replace the lock for the radio? The previous owner did the favor of loosing it.

This is awesome . . . dealer quoted me $500 bucks to replace the heater control unit. Now I jst need to find a friend with a solder iron. :)

My rx8 radio volume knob, power button, preset buttons, and scan won't respond. The radio still plays and can be adjusted using the steering wheel controls. At the same time the ambient temperature display is not working, and the ac control is only blowing hot air.

This thread helped me figure a way around my problem till I get the radio gear I am wanting. So i dont have to take the dash off more than once. So thanks =)

Great guide. Hardest part was finding the hidden bolt. After 30mins of looking I realized it was missing (seriously).

Getting the radio unit out is a pain, pull from the bottom and you'll feel a pop, then hold the left side while prying the right (lightly) and you'll see if move out a bit. then wiggle and left should pop out.

Getting to the circuit board was common sense. The instructions do not detail what you need to actually do but they provide the right steps to get reasonably close. Someone who has never worked with electronics before may have trouble here but just trust your self. The hardest part was pulling 2 plugs without giving the wires slack which I ended up having to slack them anyway. They are tucked under clips and I really didn't want to unclip them but it is needed. The one control will fall out when you remove the board, the other will only partially fall out. Not sure if it's normal or not but whatever.

It turns out the previous owner tried to fix it and soldered the wrong connections. There were massive solder deposits on a few connections (all of which were incorrect). The bolt to the radio was missing. 1 clip under steering console was broken and the carpet near there was cut a bit since I guess they tried to find the bolt.

After everything my temperature control cycles from 0-16 properly. :)

quick fix... push power button and up then find which direction makes it go to 16 and wedge something in to make it stay there so i can drive to work and not freeze my ass of at 18 degrees outside! thanks wingnut!

Thanks for the DIY!!! Just used this to fix my pot! :rock: Also the stick shift knob is really heavy for it's size, I was surprised :lol2:


Here's a really good video on the stereo removal.

http://www.youtube.com/watch?v=sG77cRRaWPM

also the hold power button + hold scan up trick does not work on my car. I don't know why... the screen would light up every letters/graphics it has...like a light bulb check. Maybe I did some wrong?

You pushed the up button on the left side. The right up button does the A/C :)

Awesome DIY!! Thanks!!!!! Saved me from freezing everyday.

Another big Thank You from someone who used your wonderfully detailed infomration to fix the heater control. It was exactly as you said, and now it works beautifully!

This fix totally worked for me. Have some pics to add once I download them

Thank you thank u to the op!

looks like i'll be doing this. Mine started to throw cold (figures getting colder on the east coast) did the test and the sucker jumps from 14 to 0 and back and then lands at 0 for a few...

SO next 60deg day its getting pulled and this fix, i hope fixes it. Thanks!

I tried this repair on my sons 2004 and I don't think it worked but on top of that now I have no power to the radio no display and u can't change the settings on the heater-like from the defrost to feet). What did I do wrong to cause that??

Great post. Thanks for the easy diagnostic.

This was the problem I was having and now I know what to do about it, just need the time/coin.

Cheers!

agreed, well i need some warmth lol. but its nice to hit the code finder to see the switch level and i just flick mine and it works... i'll get to this asap but 40-28degs and working in the weather not my cup of tea.

great diy - thanks a lot sharing!

Did for my 8 today, succeeded to loose the hidden bolt :)

To get more space behind the radio I removed the center ventilator grille. After pulling the radio unit out a bit you can see there are 2 bolts locking the grille, removing the grille gave me some extra space to access those connectors.

I tried this repair on my sons 2004 and I don't think it worked but on top of that now I have no power to the radio no display and u can't change the settings on the heater-like from the defrost to feet). What did I do wrong to cause that??

Recheck all the connections at the back of the radio and climate control unit.

Thanks to OP...

Was able to fix my daughters RX-8 yesterday!

Anyone know if this can fix problems with the buttons as well? My a/c, rear defrost, defrost, and air choice buttons all stopped working while the one in the center to choose floor/vent still works.


Thanks for the great DIY!

Finally did this after putting it off for nearly a year. Not much call for heat down here near the Gulf Coast, but it was starting to intermittently go full hot then cold, etc. Things to look out for if you are going to do it: 1) Remove the metal brace under the trim piece below the steering wheel, then a 12" extension fits perfectly level. Only loosen the bolt, then take out by hand (mine was already loose). 2) It's a great time to take the shifter trim piece completely apart and clean out the crap that falls into the creases around it. 3) Those electrical plugs are tough to separate, especially with the limited room. A miniature screwdriver came in handy there to help depress the lock tabs. 4) Once you do get the assembly out, you can get a little more slack in the wire bundles by untaping them from the mains. Mine had one turn of a very sticky blue tape on them. 5) When you get the circuit board out, it will look fine. Don't believe it...:SHOCKED: 6) It's a good thing there are guide tabs on the face plate to radio connection, otherwise, it would be very difficult to get the knife connections to line up good! 7) My 61 year old hands were nearly too big to fit behind the radio to remove and reconnect. You may need someone with skinny arms to help. 8) When you get the connections all done, do the potentiometer test, before tightening anything up. Was really nice to see a smooth 0 to 16 and back! And to see the display read correctly.

On a side note, I had two inches of water in the tail lamps after a trip through a car wash. The gasket kits that supposedly stop this cost a lot ($70 online!). So I removed both and drilled tiny holes on the lowest points, dried them out, and now they still get a little water in them, but they always drain and dry (eventually). It's a shame the two above items didn't get a more aggressive response from Mazda:pfanndina

Did this about two weeks ago (just in time too since it was starting to get cold)
great easy fix :) thanks

I need to get off my lazy ass and do this... my heater control barely works at all lol.

Fantastic post. Apparently mine's been stuck on zero for the past three years.

Now I just need to find someone else to do the dirty work to fix it. ;)

Wingnut and all the other posters, Thank You All for taking the time to post this. I know you saved me a lot of money and time. My dingleberries have been freezing off with only the seat heaters to ward off the cold. I'll tackle this on Saturday and I'm certain I'll be toasty by Monday.

Did this repair yesterday with the GF (she took the soldering iron home with her and now wants her own tool set for XMas after "helping" me replace lights, fix the clutch pedal switch, insulate for noise, and now this). Anyway, this took an hour and half including teaching time. Works perfectly now. Thanks for posting the easy to follow instructions. Saved hundreds of $ and learned more about my 8 too. Great to have this site as my main resource for learning about and maintaining my 8. I hope to be able to add something useful myself in the future.

I love you wingnut!!! This fix took me about half an hour and it worked perfectly! Thank you!

I also have the problem of no heat. After reading this thread, I did the diagnostic check and found that I had to hold the knob to the right to get the control to advance 0 through 16. I found that the 3 solder joints were bad. I then resoldered the joints and put it all back together, but I still don't have any heat. Any suggestions on what the problem may be? I'm thinking the circuit board. Is there any way to test the board. Maybe someone else out there has run into this problem as well. Thanks.

Finally did this while I was home during break. Been waiting a little over a year to do this.

Took a little over an hour to finish it up.

Thanks!

I jammed a penny in mine, works great now, took 3.5 seconds.

I jammed a penny in mine, works great now, took 3.5 seconds.

Jammed a penny in it?

:shocking:

If I had known this was going to be so easy, would have done it last year.

Thanks for the great thread!

I also have the problem of no heat. After reading this thread, I did the diagnostic check and found that I had to hold the knob to the right to get the control to advance 0 through 16. I found that the 3 solder joints were bad. I then resoldered the joints and put it all back together, but I still don't have any heat. Any suggestions on what the problem may be? I'm thinking the circuit board. Is there any way to test the board. Maybe someone else out there has run into this problem as well. Thanks.

I too couldn't get mine working...

What are some other things to check? I live in Arizona, so it's not too cold here, but it'd be nice to have heat working.

I also have the problem of no heat. After reading this thread, I did the diagnostic check and found that I had to hold the knob to the right to get the control to advance 0 through 16. I found that the 3 solder joints were bad. I then resoldered the joints and put it all back together, but I still don't have any heat. Any suggestions on what the problem may be? I'm thinking the circuit board. Is there any way to test the board. Maybe someone else out there has run into this problem as well. Thanks.

I too couldn't get mine working...

What are some other things to check? I live in Arizona, so it's not too cold here, but it'd be nice to have heat working.
The two of you should start a thread in the Troubleshooting Forum to get help on your issues.

I too couldn't get mine working...

What are some other things to check? I live in Arizona, so it's not too cold here, but it'd be nice to have heat working.

Well it seems like it partially worked, cause the heat just started working driving home now. Maybe i didn't sauder well enough. I would do the diagnostics test with the LCD screen but i have a custom nav unit and I'm afraid I can't do that with the Metra kit.

Anyways, it's working better than before... Fingers crossed :)

How do we resolder the knob. I have no experience with this problem?

^ Before you do anything do the diagnostic test to make sure the knob is the problem. If the A/C number stays either on 0 or 16 while moving the knob, it's the problem. If the numbers change as you move the knob you have a different problem. You'll need to take out the radio to get to the knob. Then you'll take the knob control apart to get to the back of the circuit board to get to the three posts that will need to be soldered. Look at the pics at the beginning of this thread to see what needs to be soldered.


If you're wondering how to solder, get a gun and some solder. Let the gun get hot and then you will hold the gun on the post and let it get hot. After a couple of seconds touch the solder to the post and it will bead off and cover the old solder making a good conection. Do not just hold the gun over the post and drop hot solder onto the post. You'll want the heat of the post to liquify the solder, not the gun. Also have good ventilation and try not to breathe in the fumes, it is not healthy to do so.

How do we resolder the knob. I have no experience with this problem?


You can also just look under the dash on the drivers side. There is a large white plastic device that looks like a large wheel with a small long piece of metal that moves the vent door from cold to hot. You can see it move when you turn the temperature knob. That other procedure works too, this just seemed to make more sense to me.

This DIY is so simple. Did this today, took me about an hour and a half. Everything went smoothly. Just dropped a couple drops of new solder on each connection, reassembled, and was good to go. Taking the metal bracket off underneath is a must to get to that hidden bolt. A little tip so you don't lose the bolt, when you loosen the bolt reach in and unscrew it the rest of the way with your fingers. The same thing applies when you put the bolt back in, reach in and start the threads with your fingers. I would recommend this DIY to anybody. One last note, make sure all the connectors are good and tight!! Or else your buttons will be doing crazy things

I've been experiencing this problem lately. If I press or nudge the knob in different directions I can sometimes get it to stick on the selected heat setting and then I get heat. Occasionally the vibrations will just send it back to 0, then it gets cold again.

Its a minor nuisance, so I'm waiting until I get an axial flow shifter, since I'll be tearing up the center column anyway, may as well kill two birds and all that. :)

^ Yea, that worked for me for a while. Soon you'll spread the connectors out further so there will be no contact :( Looks like you're in a great county for not needing the heat :)

Just finished this D.I.Y., and it was a breeze. Took me about 1 and half hours to complete mostly b/c I was searching for that stupid 10mm side bolt. Definitely would recommend removing the metal bracket under the steer column. It makes for easier access and viewing. Also, the bolt is more directly right of the twin bolts than above. Thanks for this; it saved me tons of cash.

I did this and it worked.

Finally did this DIY today... did the power/scan check and it moves freely 0-16.

THANKS FOR THE DIY!

Did this Sunday afternoon worked like a charm.....great DIY.

I had no problem performing this heater-control board solder fix besides the delay of searching for a non-existent brass bolt under the dash on the left side of my 05 Shinka's stereo (I guess Mazda stopped installing these at some point...I've had mine since new off the lot, so I know nobody else removed it)....

The only problem now is, the car won't fire up ! Everything works fine...display has no flaky connections, heater display test shows smooth 0-16, and the car cranks just fine....but never fires up. I'm getting gas, because I can smell it at the tailpipe after some seconds of unsuccessful cranking....but this car has never flooded once in all the years I've owned it off the lot brand new...and it was running just fine before taking the radio out for this heater fix.

I've checked every fuse, not just ignition-related...nothing blown....

But I admit I did not disconnect battery before removing radio and soldering control board....so that's the only thing that might be the source of not firing now...except I find no fuses blown.

I've seen posts here before that there's no anti-theft function that activates if you take the stereo out, but that sure does seem like what's going on here.

Any ideas?

this was a GREAT deal of help, did this today after work and fixed my a/c problems and also saved me over $300 of what a shop would of charged me..love the "search" button and thx Wingnut!

I've been experiencing this problem lately. If I press or nudge the knob in different directions I can sometimes get it to stick on the selected heat setting and then I get heat. Occasionally the vibrations will just send it back to 0, then it gets cold again.

Its a minor nuisance, so I'm waiting until I get an axial flow shifter, since I'll be tearing up the center column anyway, may as well kill two birds and all that. :)

I've found that you can nudge the knob in the right direction by wedging a dime between the knob and the faceplate. Worked for me as a short term fix.

It's not worth the nuance of applying these short term solutions that may break your knob. If you can't solder, find a friend that can. Buy him some beer to fix it. You won't regret it.

Hey, nice DIY, worked great for me too! I just started having this problem recently, @ 38,000 miles.

I didn't have to remove the metal bracket under the steering column, and never have, each time I have needed to get at the center console. The right lengths of socket extensions makes it pretty easy to access that bolt, really.

Thanks so much for this post. It made the job easy and saved me a lot of cash as well.

Wingnut, you rock man.

Thanks to you my temp control works now. (and I put in a grom audio box at the same time)

If you were in the nw id buy you beers. Cheers!

^ Ditto! Excellent DYI Wingnut!

I just did this and it worked! Thanks so much. I feel great now!




Misc Comments:

- I unscrewed the "Secret Bolt" with my hand.

- When I pulled out the radio I accidentally snapped the plastic piece that the knob for the 1,2,3,4 heater power thing is on. I had to use the soldering iron to melt it back together.

- It looked like the circuit board 3 'pins' were soldered perfectly fine when I looked at them. Luckily someone else in the thread made the same observation. So.. i just threw on more solder. (i have very little electronics experience)


SWEEET!

Did it today myself. Worked like a charm!! Thanks!

Did mine last night works prefect, thanks for this!

i just saved 425$ today.. thanks for the excellent thread..thanks guys

did this last weekend after running into the heat only problem while installing my metra kit.

solder looked fine on mine too, but discovered a crack under a microscope.

FYI Metra sends a document with this thread pasted into it if you ask them for tech support lol

Another happy customer here! Thanks wingnut and SamH for taking the time out to document and help out your fellow 8 owners. This DIY probably saved me the most $ for time spent.

Knowing my luck I thought this wouldn't fix my problem but it sure enough did and perfect timing considering my 8 year old 8 just started doing this since last month and blows nothing but hot air and it's AC time down here. Temp hit 90 today.

For those attempting this - It's really not that difficult taking out your radio and I've never soldered anything in my life prior to this. Just take your time securing the connections and be careful and cover the shifter after you remove the knob as that thing is sharp and put a small scratch on my faceplate. Dumb me considering this is the 4th time I removed the radio.

really like this place, still going to hang around after the fact...

figured id fix this before i go and "atempt" another trade in as mine started to give me fits, all i had to do was tap the knob and it would work.

as others have said, the biggest pain is getting the radio out, after that its cake walk. I should of took a picture of what mine looked like under the scope but couldn't get the nikon to focus right but you can see when you go to turn to hot/cold you see the 3 amegos move from the board, hince no heat/ac..
thanks agian.

Excellent DIY! Just did this, took around an hour or two, and the temp control now works perfectly! TYVM! :grouphug:


How do we resolder the knob. I have no experience with this problem?
Soldering will definitely takes some time to learn and is even more difficult without a microscope. There's plenty of online resources to research how to solder. I'm sure youtube is chocked full of intructional videos. However, being an experienced IPC Class 3 military spec solderer, I will give you a crash course on soldering and a list of tools needed to make not just a solder joint that works, but one that is extremely reliable.

Tools needed:
Solder iron - Weller is a good brand for our purpose with well priced, good quality products. 100 watt or better is recommended. Do NOT use less than 55 watts.

Fine point solder tip - Soldering the back side is a breeze with any tip, but the top is harder to get to. Use a small point tip

Flux - Use lots of it. Paste or liquid flux is fine. Any brand is fine.

Solder - Use LEADED solder. 63/27 solder is best. 0.25 diameter

Solder wick - Used to clear the old solder from the holes. any brand is fine

Rubbing alcohol - Used to clean the burnt flux

First, use the solder wick to clear the old solder. The old solder failed and therefore is junk. Get it out of there. Most likely it was lead-free as well, which has a higher fail rate than leaded solder. Do the 3 small pins first. Use lots of flux!

Once the solder is removed, make sure your solder iron is at full temperature. Start with the backside of the board. Make contact with the solder and the joint to be soldered, then apply the heat. 2 seconds of heat is your limit. These boards are low grade and wont stand up to a lot of heat. If it didn't solder fully, you didn't make good contact with the solder tip and the joint for fast, well distributed heat transfer. Try again after 5-10 seconds. Use lots of flux!

Once you have the 3 small holes soldered, fully remove the solder from the 2 large ones with solder wick. Then resolder them to the board. The reason for this order is so the part doesn't come up off of the board. Use lots of flux!

Next flip the circuit board over and solder the top. Be careful not to melt the plastic. Once again, contact the solder with the joint first, then apply heat making sure to have good contact with the tip for fast heat transfer. If you melt the plastic a little bit, don't worry, just don't get to crazy on it. Use lots of flux!

Now you have well soldered solder joints that will last. Remember, when soldering, more is not better. In fact, to much solder can weaken the joint. A hersey's kiss shape is your target when making a solder joint.

Final step is cleaning. If you have water soluable flux, you can just run warm, not hot, water over the board until it's clean. Don't submerge or drench it because the temperature control part isn't water sealed and will corrode. If the flux didn't wash away, use rubbing alcohol or even nail polish remover to clean the flux. Not as critical with no clean flux, but you must take care to clean the burnt flux off the board, which is corrosive.