Head Unit / LCD problems
 

Hi,

I have a 2004 RX8 with single disc Bose system. Very long time lurker but registered to finally post.

On a very cold day my battery decided to die. I jump started it, but my head unit no longer turns on and the LCD Display is not working (it is completely blank). The Heater/AC unit works completely fine. I've replaced the battery. I've looked over the forums to try to diagnose the issue but at this point I'm completely stuck.

Things I've checked:

I checked all of the fuses visually and with a multimeter to confirm that the Radio and ACC fuses have both continuity and proper voltage.

I checked the electrical harness that plugs into the Bose Head Unit to make sure that the 'Power Supply +B' pin was getting 12V, the 'Power Supply / ACC' pin was getting 12V, and the 'P Ground' pin was working as a proper ground. For reference to the pins I'm talking about please see this diagram:
https://www.rx8club.com/showpost.php...42&postcount=7

I know it is common for the faceplate to disconnect from the head unit, but I am sure mine is connected. At one point I completely stripped the faceplate down to just the PCB (removed all of the plastic parts) to make 100% sure it was connected to the Head Unit and pushed all of the way in. I've also read on the forums that if this is the actual problem then you can eject a CD that's currently in the player. I have a CD stuck in there that won't eject.

I assumed that I needed a replacement head unit, so I ordered a used 2005 6-CD Bose head unit/faceplate combo from an Ebay Autoparts seller. And this unit has the exact same issue.

The only thing I can think of is the Ebay seller sold me a unit with the exact same problem... but I don't really think it's a coincidence.

I finally took the thing into the dealership and they said they were sure that the head unit was bad and needed to be replaced (after charging me $100 for the diagnosis...). They quoted me over $1100 for just the parts! So that's not an option.

Any advice or suggestions would be greatly, greatly appreciated.

Thanks,

For what i just read...just replace it with a new one.

Before ordering a new one...find a local and swap radios back and forth...I doubt that you have two bad radios. When you tested for voltage at the harness did you test the front or back of the harness? Also have you tested for constant voltage at the first point within the radio?

I just test the harness at the front where it connects to the pins on the head unit.

I will strip down the head unit to the PCB and test the constant voltage the the first point within the radio as soon as I can. Thank you for the suggestion.

I put up a post in the NE Forums to try and find someone in the Rochester, NY area that might be willing to swap radios with me.

Thanks again.

I am having trouble figuring out how I can hook the radio up to my car and test for the constant voltage at the first point in the radio. Would I just strip the radio down to the basic PCB with nothing but the electrical harness attached? (no faceplate or heating unit)

If any one is within a few hours or Rochester, NY and would be willing to do a radio swap with me to test my radio let me know. I will pay for your time. I also have family in Boston, MA & Hartford, CT so if you live near those areas and are willing to do a radio swap this weekend please let me know. I am currently jobless so I could drive down almost any time. It shouldn't take more than an hour of your time and it would greatly help me figure out what the heck is wrong with my car.

In theory you could hook up constant, switched and ground to a 12V power source and test it.

I had a similar problem. They replaced the entire unit. Covered under warranty at the time. Now I have to stick my golf divot tool in the heater knob to get heat (about 30,000 miles later). Seems like the entire unit is garbage on 04's-05-s. RX-8 is like having another grilfriend, bitchy and high maintenence as hell.

But oh, what a ride....
:naughty:

So, I tried my 3rd replacement head unit today. The first time I plugged the unit in it worked fine when I turned on the car, but after that first working time now it keeps having the same problem of my other unit. (LCD/radio do not come on).

I'm completely stuck on what the issue is. could my car be frying head units? what could possibly cause this? The stereo and ACC fuses are fine... i just checked the voltage on them.

Anyone have any idea what the issue is?

rxeighth I am having the same issue as you are with my '04, I just purchased a second head unit and had the local shop switch it for me but still have the same issues....I am at a complete loss....The only thing I am thinking of doing is going ahead and getting the metra kit and being done with it altogether.

keep me updated if you end up getting the metra kit and let me know if it works out. I tried 2 replacement head units so far so I think I'm just going radio-less for now. It's so weird because I'm 100% sure that I have a good ground wire, constant 12V, and switched 12V because of the multimeter testing I've done on the front of the electrical harness.

I'm a little concerned that maybe the metra kit won't even work if it's some sort of weird short going on...

all i want is some radio in my car, lol

Have you verified that you don't have an issue with one of the Bose amps being shorted and returning voltage to the headunit?

Hi DeViLbOi,

Thank you for the suggestion. I just unplugged the Bose Amp in back and that didn't change anything. Thank you again though for the thought. I'm thinking about having an audioshop double check my harness and maybe install a new one from the battery as a last resort.

Hmm...do you think it could be the electronics in the front panel itself that are bad? I talked to another car audio shop they had no luck with the swap either and said it could be some other unit that (forgive my ignorance) provides power/controls the LCD. He said it is located in the glove box area...does any of this sound accurate? or does the guy not know what he is talking about?

I'm not sure what unit they were talking about. I was under the impression that power went to the radio from:
Battery -> Fuse Box(under hood) -> Fuse Box(near foot of door) -> Head Unit

I tried to trace the ground wire. it looks like that goes to somewhere near the glove box. Could that be what they are talking about?

I want to double check the head unit ground, but I am having a really difficult time tracing where the wire eventually connects to the frame of the car. Any one have an idea where this ground is supposed to ground to the car?

https://www.rx8club.com/series-i-trouble-shooting-95/radio-wont-turn-lcd-wont-light-up-ac-wont-work-213779/

you both have/had stuck CDs and the same issue....

His issue is a little different than mine. He has no AC/heat which indicates a faceplate connection issue. I know my faceplate connection is fine because I've stripped the faceplate down to just the PCB and tested it. Plus my AC/heat works fine and it wouldn't work at all or just the fan would work if there was a faceplate problem.

Just a quick bump to see if any new info has surfaced....

I retested all of my connections today. checked fuses, faceplate, and what I think are the grounds on the cars chassis. still nothing.

Best Buy told me they could test my double DIN connector for free so I'm going to set up an appointment to do that in the next week or so. I'm considering paying an audio install place to put a brand new electrical harness straight from the battery to the head unit. At this point I feel like it's the only option to get a radio going.

Won't help if the extra voltage is coming from one of your Bose amps though. Find the cause...then address...don't try to address random possibilities without even the smallest amount of data to back it up.

I just now realized that the two door amps are connected directly to the head unit. For some reason I thought they connected to the rear amp first. I did unplug the rear amp so I know that's not causing it. What is the best way to test the door amps/speakers for a short? Do you take the door apart and unplug them?

Would you have gotten anyone to test your unit(s) in their car? I tried to get someone in the KC area in the regional forum but haven't had any luck with a response. This new car thing with no music is starting to get to me...

Yes...you need to take the door apart to get to the door amps.

Bump for Sunday, I'm still stuck with the same issue. Wondering if any new info has surfaced...

Hey, I still haven't had a chance to unplug my door amps. I've had an insane stomach flu for the last week :puke::puke::puke:

...so I haven't really worried about my radio. I should be able to test the amps in the next couple days though and I'll let you guys know the results either way.

A bit of an update for you from my side... First I tested all my fuses for a 6th time, then checked the harness and everything checked out fine. However, last night I drove out to meet someone with an 8 and we swapped head units.

My origional = Dead in his
My replacement = Worked in his

His working = 5 blown fuses in mine.... (The room fuse (very bottom) in the kick pannel)

I am completely at a loss, so I think I am just going to suck it up and take it to a shop and have all aftermarket installed.

Ya, my LCD/head unit has some issues too, kind of the opposite of your problem. All my dials and everything works.

Pics:
https://www.rx8club.com/rx-8-discussion-3/radio-stereo-lcd-display-problems-contrast-198309/

So I finally got around to taking my doors apart to test the side Bose amps and I can confirm that its not the problem.

I'm completely stuck as to what the issue is. I'm probably selling the car sometime over the summer anyways. I can't even think of a way to diagnose the problem so it would probably cost a fortune to have the dealership figure this out. I'll just eat the lost value when I sell the car.

EDIT: I was at Best Buy today chatting with the car audio guys and they said they can test the harness & speakers for a potential short for only $20. I set up an appointment for next friday. I'll update on what they find.

Subscribing...
 

I'm having a similar issue on my 2004 non-bose. The radio stopped working. The LCD no longer displays anything. My AC and heat still work. I purchased a used radio from another member and the issue is the same. I've checked every fuse. I've completely disassembled the radio and reassembled it. I'm at a loss.

I took my car into Best Buy and they checked it out. They told me that they are sure there's a short somewhere, but it would be near impossible to find. The power supply is fine up until it reaches the actual head unit.

I know it's not my amps shorting. How can I diagnose where the short is coming from? Can I take the wiring harness completely apart and only plug in the ground, Constant 12V & Switched 12V wires? If so, would I do this by just 'snapping' the plastic pieces off of the harness?

Pardon my ignorance...I do not have a shop manual or anything but I was wondering something. I have pulled everything out again and noticed there is a lot of electrical tape around my wiring working back into the car which makes me think someone got into it and was hacking away splicing and crap I plan on pulling all of it off and checking the wires and such but if I cannot find the short in my system does anyone know how the wiring is setup in the car running through the dash? is there a harness it originates from or is it all hardwired in.

My thought is just if I cannot find my short in the system can i simply purchase the wiring from a parts car and simply re-run the wiring without much of a problem or is it hugely more involved than that? I know it sounds desperate but it is killing me having to use my iPhone for music in the car with a nice system that is there just non fuctional.

The wiring harness that comes to the back of the radio is wrapped in electrical tape from the factory. Ordering a complete wiring harness for the car would involve you stripping the car to install it as it really does run everywhere.

well...good news and bad news i guess...honestly I had kinda hoped that the previous owner had tried something as it probably would have made finding the short easier. But I guess it is good to know that he wasnt messing with things that he shouldnt have. I am just not used to seeing electrical tape from the factory i guess.

I had Mazda look at my car. They're telling me the audio control unit is broken and needs to be replaced. The part is $600. Anyone know where I can find one of these cheap? :(

there are a couple cars being parted out in the ForSale thread.

I want to say I just saw a bose headunit as well in it's own FS thread.

What exactly is an audio control unit? It sounds like what the installer was saying went bad in my car. ( does anyone have a diagram that shows location etc?)

Bump..any results to this thread? Same problem..

They replaced the audio control unit and that did not resolve the issue. I still don't know exactly what that part is. When i asked for the part number they gave me the part number for the radio itself. They told me they would need to order more parts and call the tech line. I haven't taken it back since then. I'm annoyed that they can't figure it out.

Pretty sure i'm just going to go with a Metra kit after reading all of this

Has anyone solved this yet? I'm not sure but I think it might have more to do with the battery. I bought a Optima Red Top and installed it yesterday. I also added a disconnect switch to the negative cable and put a new terminal on the other. Seems like everytime you play with your car you gotta disconnect neg cable and I'm hoping this will be easier than removing it every time. All this meant some wiggling even thought I tried to be easy. When she started right up but I don't have radio or temp display now. I've been looking online for solutions and while alot of people were working on their audio units when this happened there are some who jumped/changed/disconnected the battery and when the car was started the display was out. I'm checking my battery connections tomorrow. I have a feeling it is in the harness?/wires by the battery.

seriously i'm having synchro problems and i just literaly parked my car for an hour, got back in it and plugged in my ipod and my headunit wasn't working. the radio itself works on am and fm, but you put in a cd and it doesnt play the cd and the cd button doesnt work. I'm about ready to sell the god damn thing and i just put full turboxs exhaust on it

What's that got to do with this thread?

Try and focus.....

Disconnect negative battery cable for a few minutes then reconnect. Sometimes disconnecting the battery, jumping it or a new battery will screw up computer system making the car think it is being stolen.

yeah i tried disconnectiong the battery last night, woke up this morning and reconnected it and it still doesnt work. it also kicked on the loss of traction light and the dsc light was flashing. had to drive it down the street and back, shut it off and start it 3 times before they stayed off. cd mode still doesn't work, even if i put a cd in. only thing i can think of is maybe the lint in the bottom of my iphone shocked it somehow and somehow fried it.

Traction and DSC came on because you disconnected the battery and then didn't take the stearing wheel to the left and right fully.

ahh i see, well thats simple enough, anyone know of what i could do for the cd player, i had it apart. didn't notice anything. checked all connections, everything works except the cd button and putting a cd in doesnt get it rolling either. So i'm not so sure its just the faceplate lost contact with the button or whatever behind it because you think putting the cd in would still start it. so i found a used one with 100 percent satisfaction guaranteed on google, think its worth the try? or pull the circuit board out of the faceplate

What happens when you use the mode button on your wheel? Im pretty sure that switches from one source to the next...I could be wrong though...I never use the button.

it just cycles it through am and fm. im going to rip the face plate apart tonight i believe to see whats wrong

So I've still been unable to diagnose what is wrong with my radio. The audio shop I had it checked out at said my only option is to replace the stock head unit with metra kit as well as every speaker and all of the amps. They said that one of my speakers might be shorting the head unit and it's not possible (or too expensive) to diagnose what speaker is causing the short. Does this sound right? The said if I just replace the head unit with a aftermarket I could have the same issue I was having with the 3 BOSE head units I've tried. I mean if I HAVE to I suppose I will buy all new speakers, and amp, a sub, head unit, metra kit, and pay for an install. But I wanted to double check if anyone has a better suggestion before I spend a few grand just to get some music in my car :sad: ....

Thanks for anyone that has a suggestion.