96 AC problem (HELP)!

[Wamp]

Have a problem with the AC on a 96. (This is the Automatic climate control option) When the button is pushed it does not turn on, It takes several times of pushing the button until it will come on. What can I check? Anyone that has had this problem please let me know.

 

[MARKSC4]

I had that problem and the problem that the buttons wouldn't light up. Both went away when I pulled and re-seated every fuse that had anything to do with AC and/or ECC.

Follow the owner's manual for the guide to fuses, there's a bunch.

I hope it helps.

 

[vettenick]

What you can try is remove the controller and take it apart. Usually what happens is a film develops on the back of the buttons which is actually a rubber membrane with carbon impregnated into the rubber. If you remove the membrane and clean the contacts on the back, this usually restores contact. Use alcohol or brake cleaner on a rag and wipe VERY LIGHTLY--don't rub. Good luck!

 

[froggy47]

Also could be the programmer - was on my 96 - new programmer fixed all.

 

[Robertwav1]

I think that's what "vettenick" meant. The thing comes apart and can be cleaned. I have had success in doing this on my 93. Stll works...just needed to be cleaned.

 

[froggy47]

The programmer is way under the dash wires on one side vac tubes on the other.

The "controller" I guess means the buttons you push. I have had keyboards like that with a membrane on the back that makes/breaks connections. Cleaning it only works once or twice, then it's basically worn out.

 

[alan ream]

What you can try is remove the controller and take it apart. Usually what happens is a film develops on the back of the buttons which is actually a rubber membrane with carbon impregnated into the rubber. If you remove the membrane and clean the contacts on the back, this usually restores contact. Use alcohol or brake cleaner on a rag and wipe VERY LIGHTLY--don't rub. Good luck!

I have a 95. What is involved in getting to this controller. Is it directly behind the buttons??

 

[vettenick]

The console plate has to be removed first. The storage door must be removed in order to get at the rear screws for the console plate. Once the plate is removed, the center dash panel can be removed. The ac control switch is right there. If you want service manual instructions, just send me your fax and I'll get it to you.
Just be patient and careful-everything is plastic and fragile.

 

[Spinman]

Vettenick -

Do you have any hands on experience removing the control head?

I'd like to remove the head on my '90 (for cleaning / inspection / diagnostic testing), but am having difficulity sliding the unit past the curved dash bolster that needs to be pushed out of the way.

I did remove the screw down a bit lower near the radio so that it would flex - but apparently not enough. I'm afraid to really push it out anymore, in case I damage the panels...

Is there a trick?

 

[Spinman]

Just thinking out loud...

MARKSC4 commented that he resolved his problems of buttons not lighting and recognizing input by removing and reseating all the fuses applicable to the AC / ECC. Assuming that they were seated in the first place - wouldn't the same results be achieved by merely disconnecting the negative battery cable for 30 seconds and then reattaching. This would let the programmer logic be reloaded... (which should not have any effect on button activiation anyway) -

 

[Spinman]

My problem is that a variety of the buttons refuse to work sometimes, and work othertimes. There is no consistency as to what refuses to work and how long it is out of service until it starts working again. As noted, I've had suggestions that I needed to replace the programmer, clean the conatcts on the programmer, rebuild the programmer, replace the control head, clean the contacts on the control head.

A recent suggestion may be the most logical:

"The A/C programmer - control heads are different when you get into the 90 model and later. Haven't ever taken a '90 apart. My '86 actually had 2 sets of connector strips that needed attention. 1st was the cable connector to the control head and another connector inside the control head to the push button face. Cleaning consisted of taking a pencil eraser (good 'ol #2) and rubbing away all the corrosion. Next I traced back on the wire harness and made sure the ground wires were cleaned and tight. The push buttons on the front just get full of junk and need to be cleaned out for smooth movement (like spilled coffee and coke).... The Programmer was a different problem. There were 2 power resistors that had failed and I had to replace to fix. (batee photo showed hot spot on board under resistor). The programmer is actually the device that manipulates the vacuum amongst the various dampers used to control air flow around the vents. It is dependant on the control head to function (kinda like brains and brawn). I pulled the vacuum hose connector off front of programmer and check the damper movements with my vacuum bleed tool (Mityvac). My suggestion, work thru your manual and chase down the various ground connections in the harness near the control head. The kind of intermittent problem you describe sounds like a ground problem... hope this helps"

A little info on the C68 Electronic Climate Control system
http://www.batee.com/corvette/acrepair/c68pgmrboard/c68.shtml

 

[vettenick]

SPINMAN, the fact that you're having inconsistent operation, leads me to believe it may well be the control panel. If it were a power problem, I would think nothing would work and be consistent. If you e mail me your fax # I'll get you the procedure to remove it.
By the way, your system is supposed to have self diagnostics. So, if by chance, it's something other than a contact problem, you can get some type of lead. I can fax you that also if you like.
By the way, the GM manual says to remove the upper trim panel pad as one of the steps in getting the control out.