DIY: Climate Control Blower Resistor Fix and Test
 

Figured I would contribute my experience with the climate control (heater and A/C) blower motor.
I have just purchased a 2006 Shinka edition and got a really good deal but there were a few problems.
The most annoying one is that the blower only worked on the high speed setting. Thanks to StealthTL for directing me to look at the resistor block!

So, if you are having a problem with your blower, weather you are missing speeds, or simply only have high Read on. Of course if it doesn't work at all, check your fuse first :-)

The resistor block for fan control is mounted on and in part of the duct work.
1. You need to remove the glove box. Search on the forum as plenty of people have done a write up on that.

2. Remove the relay in the first picture. The one bolt holding it has a green arrow pointing at it. No need to disconnect, we are just getting it out of the way.

3. Remove and disconnect the part seen in Pic 2. This is the resistor block. There are two screws holding it in. Get a LONG Phillips, it will be so much easier.
Pic 3 just gives you a good reference to where it is.

4. Remove the metal housing on the block. There are 2 tabs, just bend the metal housing out a bit at the arrow in pic 4 and then pry up.
Here is where you can take different paths. If yours is like mine was and only high works, it is most likely caused by the piece of melted solder in pic 5. If not, jump to step 8.
Apparently mazda thought it was a good idea to put a piece of solder to bridge to the output connector just in case the resistor block got too hot so it would break the circuit.
In my case this was caused my the berings going dry on the blower motor and having too much load at that point made the resistor block heat up, thus melting the solder.

5. With a good wattage soldering iron (and some solder wick if you have it), clean out that piece of solder from the holes and it should look like pic 6 when you are done.

6. Use a piece of standard size electrical solder and cut it to about the length you see in pic 7.

7. Carefully solder the ends of each side and melt it down flush.

Now let's test

8. Pic 8 shows the connector side. Put one lead on the top right terminal, marked H.
Test Resistance between H and M2 (bottom right) should be 0.39 Ohms; Between H and M2(top right) should be 1.14 ohms; Between H and L (bottom left) Should be 3.14 ohms
See Pic 9 for a illustration of this.

If any one or more of the above give no reading, the possibility is that one of the resistor coils have gone bad. I have no idea how or what to replace them with, so that is up to you...fix it or buy another!

Alright, finally put it all back together (of course)

Hope this was helpful to someone out there!

I realize this is an old post and the OP probably won't see this... but just in case: please accept my thanks!

And for anyone who is encountering the issue described in this thread (heater fan only working on highest setting: 4), this fix absolutely works.

I had a critter build a nest in the air cabin filter box and after cleaning it up, I noticed the fan stopped working on all but the highest setting. I followed the instructions outlined above and was able to repair the resistor module in about 10 minutes with a bit of solder.

I can't even imagine how long it would have taken me to trace this problem back to the source on my own.

Wow, it has been a while! Glad I could help someone. This site has been a great help for me as well.

Spinx Haplo. I'll be buying the soldering gun soon. I wanted to know how much wattage will be enough to fix it. Thanx in advance

Just buy one of the cheap harbor freight ones. They work just fine. 30 Watt Lightweight Soldering Iron

or buy the gas one

Pen Torch with Soldering Kit and Knife

Awesome awesome awesome... Thanks to these guys I was able to get my resistor to work properly again

Spinx Haplo, Thank You! Thank you! That was a quick and easy fix that worked perfectly! My 2010 R3 just developed the same problem with the blower only working on the highest setting. After coming across your post, I was able to fix my own car.
The dealership, without a doubt, would have charged me $$$ and given possibly given me a runaround while their employee toiled with test after test at my own expense. Not only did your knowledge save me money, time and patience, it gave me the great satisfaction in being able to fix my own car :) THANK YOU!

Glad I could help!

Hey, just curious here as to how this was not working. A while back, my "1" fan speed setting stopped working. A few weeks later, "2" crapped out as well. And by crapped out, I mean it acted as if I had turned it to "0." I noticed, however, that if it was set to 2 and I pushed on the fan speed dial, the fan worked. Do you think that's the same issue, or something in the heater control unit? Thanks.

In the case of the resistor it either all work or only high. Sounds like a failing selector switch to me in this case.

Yeah, that's probably it. Sound like an easy fix, or should I replace the whole unit?

Wanted to give a thank you for this as I am diagnosing and trying to fix my recent hvac failure.

I had a problem where one day it didn't want to blow until I put it on max, then worked normal. The next time I started the car nothing came out, turned it on and off a couple times and got a small puff of smoke and no more fan.

I pulled the blower motor, and tested it with a quick 12v source and it was strong. Pulled the resistor next from information from the forums including this thread. I will mention in my experience, removing that cover to check the solders, using the nearby circular holes was much easier for me to bend the metal than at the clips themselves.

For me, the solders appeared fine, but one of the coils were darkened/blackened, another had a 'rainbow' type discoloration, while another looked 'normal'. If I can find my tester will pick up another and verify the coils are fried. The replacement from auto parts stores are $38-49; all of them in my general area do not have them in store but claim to have them in stock from their site for home delivery. I have always avoided ebay, that's an option for some, saw one close to $20 iirc. The only one I found on amazon says 1-2 months average time to ship ...

Getting to it is much easier than you may think, the glovebox comes out really easy and gives you a clear view of what you are doing.

The blower motor itself uses a hex/star head on the 3 screws (whatever those are called, it's like a 6 point philips?, can use a flathead as well).

Good luck to any others having issues!!!

Is it just me or are the large images not loading? I have the same problem, have already had a dealership diagnose it as the resistor motor and want to try the fix on my own (even though I just ordered the part which is back ordered for a week). Can anyone send me the larger pictures?


*** EDIT *** Got the images to load in another tab (have to right click them). Thanks for putting this together. Crossing my fingers it fixes my problem which is that I only have the high setting and the AC compressor will not kick on with it on high, but if I go down a fan speed the AC compressor kicks on but the fan does not. Will report back if that issues is fixed by this fix.

Thank you so much for this. I was able to get my AC working again. If anyone out there experiences just high speed fan without the AC coming on this is the fix. Also, those little wires get very, very hot (they glow) so make sure that you dont do like me and let it hang without putting it back in its place to test it.... it will burn you good.

It's awesome that a DIY I posted 8 years ago is still helping out! This was the first one I had ever done. Also i have to report that 8 years later the fix is still in place and working fine.