C5 Climate Control dim/dark display fix
Just trying to save the next poor guy some time for looking all over and following all the various links from everywhere

Hope this helps!
For the first steps, find pictures and more detailed instructions where I did, at http://www.vetteessentials.com/instr...zel_howto.html
Their list of tools is for a bigger job, you wont need all of the ones listed, you'll need others for actually fixing the control unit, and you only need to go to step 3g, no further for this section!
***If you have a convertible with the body colored "waterfall" you will have to remove it first. If not, skip this step. 4 screws total, size 15 torx screws, two on the top, one on each side towards the bottom. Just gently pull up to remove it.
Remove the console - Gently remove the Active Handling trim plate and wiring connections beneath it and to the console. Remove the 4 10mm nuts. Pick up only the back of the console to get it over the rear bolts, then slide it towards the back to get it out from the front bolts. The front is slotted to slide all the way out.
Remove the instrument trim panel - Gently pry out the trim panel to the left of the ignition switch, and remove the ashtray. Remove the 3 #15 torx screws. GENTLY pull the panel only a little ways! Back towards the top, and up at the bottom/back where 2 of the 10mm nuts were removed from the front of the console area (behind the shifter). Remove the cigarette lighter power. ***If it's a 6spd, remove the boot carefully, I pulled mine up, but this site says you can push it down also*** Once you've verified everything is free, carefully pull it out and set it safely aside.
Again, I highly recommend going to the following site http://www.vetteessentials.com/instr...zel_howto.html for pictures and a more detailed step by step instructions for the above steps.
The following steps are not found at the above URL.
Now you have a clear shot to your Climate Control unit! There are only 2 screws holding it in place. I'm sorry I didn’t get the size of them, but they're easily accessible to test a few sockets to find the perfect match
Remove the screws, pull the unit out a little way, and remove the connector in the back. Pay attention to the connector, there's an area you have to press to release the clip to be able to pull it out.Now that you have the unit out, take it to a safe place, preferably the clean worktable you will be finishing the work on it

Carefully remove the 4 screws on the corners holding it together. They are small, and have very coarse threads, so use a hand screwdriver style tool preferably, NOT a drill, if you only have a ratchet set, just be very careful not to over tighten it when you're done!
The following was ninja'ed from RPOZ4Z at Corvette Forum http://forums.corvetteforum.com/show...1316227&page=2 on page 2 post # 24. Thank you VERY much RPOZ4Z for putting words to sight so I knew what the hell to solder!!!
It works like new!
I'll post some pics in a little bit.
basically I just touched up the soldering on the big surface mount resistors on the power supply board.
here are the pics..................................
remove the 4 screws from the back of the HVAC control, when you take it apart this is what you will see.

remove the 4 screws holding the power supply board to the back cover, and flip the board over.

there are 8 surface mount components (outlined in yellow), these are the "culprits".

with a soldering iron, touch up the solder joints on these components, be careful, due to the bad soldering, they may move from their locations on the board, if they do, use a pair of tweezers of small needle nose pliars to reposition them and hold them in place while you solder one side. don't use a soldering gun or too much heat, chip components tend to get damaged by too much heat.


(please pardon my crappy soldering, I did this in a hurry on my kitchen table right before dinner!)

The tip it came with was not ideal, but it finally got the job done!I tried to see which seemed loose and only solder those few. Don’t bother trying, either you wont be able to tell, or you'll break them off looking for the loose ones. I fixed the 2 obvious ones, and went out to the car to try it, but only got a very dim light. When I went back and soldered more they were practically ALL broken on one side

Be careful to try and hold them in place so they don’t move if you happen to solder the good end first. I had one come completely off the board, and it was very hard to get it back on. I eventually wound up putting solder on the contacts on the board first, then putting the chip back on and soldering, it was a pain. I just rested the back of a tiny jeweler’s screwdriver on them to keep them in place, it doesn’t take much.
When you finally have them all done on both sides, carefully put the unit back together. Be sure to line up the pins on the back cover, and be careful with the small coarse threaded screws. I put them in the hole, turned them backwards until I felt where the thread was and then gently screwed them in until tight. You do not want to torque them at all, it will be obvious when they're tight and you're against the circuit board. Same with the screws that hold the casing together.
Now before you put everything back together in your car, make sure you turn the ignition on to make sure it lights up! You don’t need to start the car, just put it in the on position. Assuming everything works, CONGRATULATIONS! Follow the steps in reverse order to put everything back together, reconnect all the electrical items, and make sure not to strip or over tighten anything. One thing I did notice is the screw behind the ashtray seems loose when you're putting it back together at first. It's just the nature of the clip. Once the dash is in position and you snug it up it will get tight.
Now that I know what I'm doing, it really is a quick job! If you read up and study the pictures first, it should go pretty smoothly long as you or someone you know can solder ok

Cordless Coldheat Soldering gun - $19.99
4 pack AA batteries - $3.99
.022 dia High Tech Rosin Core Solder - $3.99
Saving $500 and a day spent at the dealership with no car - priceless!
-ALSO!!! If you DONT want to risk soldering it yourself, try a local reputable electronics expert. Long as you can show him what's broke he can probably fix it. Or if you have time to wait for mail have an expert do it for you!!! I don’t know this person at all, I just found the following in my search!
From member rws.1 http://forums.corvetteforum.com/show...t=David+Ruberg post #2
check itout tonight.
If dim it can be repaireed.
Many here have done it themsleves with a soldering iron
try searching in C5 tech use key words Dim, HVAC,cold solder,
I sent mine out for repair Less than $50 with a 5 year guarantee
CF member mandigital ( David Ruberg)
e-mail digitalguy_1@charter.net
Re the tire sensors... You are out of luck.
the early (pre-'01) system cannot be turned off.
If you do not want the light you have to install new sensors.
MUCH thanks to everyone that did the legwork everywhere to get all this great info out there, I hope this makes it easier to find and read through all the various steps!
It should be a Sticky

Here's the original for reference http://forums.corvetteforum.com/show....php?t=1316227
EG


At some point, I'm gonna have to do this, my display has gotten dimmer and dimmer. Thanks so much for the writeup and getting everything in one, easy to understand thread. :cheer:
Thanks again to those that did all the various posts that made the job rather painless for me!

I believe it is the AC button and the off button.
I guess while it's apart I'll install my MTI 6 shooter that just showed up last week.
This "while it's apart" phenomenon is dangerous. I went from buying used LG Pro LTs for $1000 to saying "while it's apart" and a few weeks later am doing heads and cam. LOL.
The Best of Corvette for Corvette Enthusiasts





I used a weller soldering station to do mine, I don't think the iron damaged the board unless you used too much heat and damaged a chip component.
you might also try looking at the board with a magnifying glass for solder bridges.
Last edited by RPOZ4Z; Jan 2, 2007 at 02:50 PM.
I had tried this about a year or two ago with no luck, but didn't know which components were at fault. I did the 8 resistors and now after years of not working I couldn't be happier with this inexpensive fix. Thanks to everyone for this great forum. By the way, I had a resistor come off the board and checked it with my meter. It was 244 ohms, I guess that is what the "241" stands for.
I was also thinking of doing the LED mod on the unit. Will doing the mod fix the light problem or do I need to solder those resistors anyway?
It's still the same unit though, so the removal of the unit will be the same, you just need to figure out what else in that little black box is broken.
No clue if doing the LED mod to change colors would help, I wouldnt think so though.



Radio Shack sells a 60ma bulb that is very close to the stock 70ma. I recommend replacing all of those at once...
The LEDs are controlled by the buttons each one represent but I'm not sure where that circuitry goes. If you have a few LEDs out try replacing them...
And that's all I know!
We had read about the fix shown here, but didn't want to chance screwing it up on our own. We feel this is the best $99.00 we've spent, so far. All of the pushbuttons and the display look just like new for half the cost of a new unit.
I don't work for this guy and haven't included his name on purpose. I just think he does some great work and made our problem go away quite easily.
Well I got to say you helped me I took all of your gathered info and put it to use.
It took about less two HRs I took me 15min. to remove the unit from the dash. then I took it inside that took less then 45 min. to complete and then another 30 minutes to install. WoW I have a digital display that works, I have been driving around guessing what was on, the defroster or the foot or the vents you know , well how could you you were'nt there I was and I did not know where the air was coming from or even the outside temp. If I sound a little excited I am! you don't know what it's like when you get used to the simple plasure of the vette, I want to thank you for taking the time and helping out Thank you













