engifineer

The board on an 05-06 is laid out differently and doesnt have this issue normally. Like he said above it is most likely another issue. IF you did make sure you got another unit from an 05-06 and it still doesnt work, then the likely cause is something in the dimmer control wiring or circuit. But if you got an 07+ unit then it wont work in your car no matter what.

RustystC3208

I will be sure to double check and go ahead and check the wiring out as well. Thanks for the advice/input

RustystC3208

I indeed found the problem. 4 resistors on the speedo cluster got super hot and fried. Causing all of my illumination lights to not work. 12 bucks later.. all better

engifineer

Make sure you clean that board very well (I use rubbing alcohol and an old toothbrush to clean them after I work on them). Something made those fry, and I would say it was likely a short somewhere.

RustystC3208

Either a short like you said. Or a fuse with too high of amperage that was in there, let too much power through. Ever since I fixed it, I of put the right size of fuse in and i've gad the lights on every time im in it. And in the past week, id say it would add up to about a good 8 hours on them. So I'll cross my fingers and hope they never fry again. But at least I'll know where to look

engifineer

Fuses dont let too much power in.

Think of it like this. Current is drawn from a device. If I have a 12V power source and a 120 ohm load, it will draw 0.1A no matter what. You could have a larger capacity 12V battery (like a higher CCA rated one), larger fuse, etc and it will still draw 0.1A. You could have a bank of 100 batteries in parallel (still 12V overall) and a 1000 amp fuse ... and it would draw 0.1A.

The fuse is there just to protect the devices and wiring. In the circuit above, I may design the wiring and power supply to be capable of 1A continuous. That means I would want a 1A or smaller fuse in the system so that if a short does occur, the fuse would pop before the wiring melted and turned the car into a giant ashtray So the fuse could not have caused the issue.

If something fried, then something was wrong. Could have been a short or a sudden over voltage situation. The latter is less likely since the system is designed to operate at running voltage. So unless the voltage regulator for the charging system was allowing an over voltage, which would have caused other issues, then you are back to some sort of partial or full short.

If an LED swap has been done and for some reason the wrong resistors were used, that could cause an issue as well.

RustystC3208

Simple enough to understand.
An LED swap was done.
So I do believe sir, that you are correct. Lol

engifineer

they should not have needed to swap the resistors on the cluster led swap like they do on the hvac swap. However, some do to make he gauge leds brighter when switching to blue, green or white. If they used too low of a value then you may have more issues with leds and/or resistors failing in the future. Also, if the swapped the resistors and used too low of a power rating on them that could also cause them to fail. Resistors are sized in power increments, like 1/8th watt, 1/4 watt, etc.

If you can let us know what color the led swap was, and possibly still have the resistors you removed or pics of the board with them on it, I can maybe let you know if it looks right or not. Since you know which ones you had to replace, you could let us know which ones on the board they were and the part number you replaced them with. That is a good way to check if it was a component sizing issue or a short somewhere.

If it was a short, chances are it was a small piece of solder that was still on the board when they were done, but broke loose and shorted something out.

SquallLHeart

i didn't do it.

hmm.. now i'm curious..

ravishankarasu

I have the same problem. I am no mechanic or soldering expert. I took off the Center dash. The board looks different. I think I just added the pic as an attachment.

cant seem to just paste it here. Let me know if you can see it.

If you know this board as well, could you please tell me where the soldering needs to take place? thanks!

engifineer

You need to take the board out of the housing by removing the screws in it. Then flip it over. What you are looking for is on the other side.

jazfromhouston

Hey engifineer, I wanted to personally thank you for this write up and the information you took the time to provide. When my car was under warranty, I brought it in, and hassled with the dealership for 2 hours before they told me they would replace it and not charge me a single dime. Needless to say, a year after, (warranty just expired) it went out again. I used your info to fix it, and no issues now. THANKS AGAIN!

SquallLHeart

sweet!! that's always a wonderful thing to hear.

engifineer

Definitely good to hear that people are still getting use out of it!

ravishankarasu

Ok, finally took the center dash out again and gave to a friend who does soldering. He did what was written, and I was very excited to see if it would work, but it did not. The lights on the clock, for example, go on when I turn the car on, but still turn off when I turn on the headlights. Could this be a fuse issue or something else? In general with the headlights off, the clock light remains on and when I turn on the headlights, the clock light turns off but then every once in awhile it will light up for a second or two...then go off again.

Thanks!

engifineer

Has this board had an led swap performed on it? Is it any color except orange/amber?

ravishankarasu

This is the first time I ever took the board out (or anyone has that I know of). I bought the car new, so it should be whatever color was original stock. Its kinda fun walking around with the center dash of a tc...kinda looks like a chest armor plate..hehe

engifineer

It sounds like a bad connection. Could even be in the wiring, or even a bad solder joint on an led. If it is only the clock that is going off and on and not the whole hvac, then one thing to check would be the solder joints on the leds and resistor under the screen, which requires removing the lcd.

tapply4894

I have an 08 Tc and this just happened to me about an hour ago after I installed a new radio. Will this fix work for me or is the motherboard different?

usafscion

iTrader: (4)

Huh.... this is nuts... I have the same problem. 07 TC and I don't remember if this all happened when I changed my stock radio for a pioneer... but I can see that the lightning off of the clock works but I soon as I turn the headlights on, the lighting on the clock goes out. ( and no other lighting on the HVAC ) (all functions still works)
any one knows what this could be?