Wondering if anybody here has a good understanding of this system. I have the factory manuals, but they don't get in-depth on this.

The controls were flakey and wouldn't work sometimes for the last few years, especially on cold damp days, so I figured some moisure gets in behind the control buttons. After a few hours in the hot sun pushing the buttons would cause everything to work fine again.

Now the controls are permanently stuck on high A/C defrost.

I reset the programing by disconnecting the battery and after reconnecting the battery it would go to auto, throw a code 1, and then right back to high A/C defrost. The code 1 is past limit on the mixing door I think. Then I took out the fuses and reset the programming and the code went away, the system goes to auto on startup. Then it goes back to defrost by itself but the temp is now set at 76 instead of 60. None of the buttons on the control head do anything to change temp or fan speed or mixing door position. But I can get it into diagnostic mode with fan speed buttons.

So what is this telling me where to start looking for the problem? Electronic control head and buttons or under the dash at the mixing door? The computer brain thingey?

Any ideas would be helpful.

 

Did you look into the code 1 in your manuals?
My hunch
#1: (w/o me looking at the system) you have a defective control panel. If it's heat related, you can use a hand held heater blower (they use them for heat shrink tubing in electronics) to isolate the failure by getting at the controller in the dash, running the system, then pointing the blower at the controller & heat it up. It should straighten up as you described when it was in the sun.
With the heat removed, it'll return to a defective state. = defective controller.
- or -
#2: What I would check first before running down the the dealer is all the grounds associated with the a/c.

Hope this helps!

 

I looked and looked, and I couldn't find anything that described what mine was doing in the FSM. The diagnostic procedures don't apply I guess if you can't work the buttons.

But it is moot now. I shorted it out the circuit board on the shifter fiddling with it with the car running. So I need to buy a new control head anyway.

Thanks for you input, and I bet your right thats what that 1 code is that it was throwing on start-up.


Its got a Serv. No. 16192608 sticker on the part, and that comes back as a CONT REM on gmpartsdirect for $112.24. I assume that is the GM replacement part number?

 

I know it's fried but in case anyone else has the same type of problem here is a site that is full of everything you want to know about the controler, how it works and how to fix it.

http://www.batee.com/corvette/acrepa...oard/c68.shtml

 

I can tell you for a FACT that this will help, if not fix it completeley!
I took the AC control panel out of my '96 when it started working intermittently....and it was VERY intermittent. I took and erasure and used it to rub and clean all the pins....put it back together....guess what? NO MORE PROBLEMS.

 

Thanks for the link. Now I know what the "programmer" is without taking it out to look at it.

 

Go to a dealer & ask them to look it up on microfishe. You don't have to order it then, but you'll have the part #. Also, it might be least expensive, sometimes it is.
Sorry to hear that. Yeah, I've done that myslef working on dashes!
So what did you short out? Can you see a fried part or was it catstrophic? I might be able to help you repair remotely, if it's an easy fix. Depends on the damage done.

 

I don't know what exactly shorted out. There are a bunch of transistors and two fairly large IC's on the board that are probably not 12V friendly. The soldered side of the board touched metal on the shifter and the LCD and LED's went dark, never to come on again.

I checked all the fuses, because I was hoping one blew, but they were all good.

I'm working out in the driveway in the dark because my race car and trailer are is in the garage in case it rains. Not my favorite way to work. When I got home from work last night the wife so much as demanded that she wanted to drive the Corvette tomorrow and she wanted the A/C to work right. That's what I get for trying to please the wife.

 

Did you check your fuse? You probably did, but I didn't see that mentioned. Check all your fuse labels in the box.
You probably did kill the curcuit board. Do you have a Corvette wrecking yard nearby? They might have that part.

 

I'm kind of scratching my head on this one. The control head comes out after you have removed the radio bezel and console, and the two wire harnesses have barely enough length to them to connect with the module slightly out of the slot.

How did you touch it to the shifter with it plugged in??? Its completely contained, you have to remove the four screws and button panel to get to the boards.

The buttons and LCD are illuminated with those little LED bulbs. I think there are 5 of them. P/n 16051463. Using a small blade screwdriver, rotate 1/2 turn to remove. I just replaced three of them.

The 01 code was telling you it was a seeing a fault on D13 (pin on controller head) or the mix motor/door will not go to hot or cold position when the controller is telling it to. Did you check the alignment of the temp door. Its on the heater core and has position indicators on the heater case.