1993 A/C Control Panel Problem
Thread Starter
Instructor
Joined: Jan 2005
Posts: 224
Likes: 2
From: Deerfield Beach FL
1993 A/C Control Panel Problem
Hello All.....I have a 1993 40th Coupe with 15K original miles, car has been in the family since new and has always been garage kept. My problem is the A/C control panel buttons and also the thermostat control work intermittently. For example, sometimes I can turn the A/C on, but sometimes I can't, same with the thermostat control. At times I can only make the car cooler inside and other times I can only make the car warmer inside. In the summer time I just leave the A/C on all the time because it will usually not turn off, and if it will turn off there is a good chance it will not turn back on. It seems when the weather gets a little cooler outside the buttons and controls work better than when it is hot outside, which is weird.......I seem to remember reading an article about this problem in either Vette or Corvette Fever magazine years ago....I have been going through all my back issues but can't seem to find the issue that I read it in......Any help on this problem will be greatly appreciated. I know I can't be the only ne who has experienced this problem.......Thanks for any and all replies.....
Pro
Joined: Apr 2005
Posts: 590
Likes: 0
From: Boynton Beach, FL
I can't speak factually without the shop manual in front of me but I do know A/C the controls on a 93 are vacuum controlled. There is a snake pit iof vacuum lines from the controller to the various valves and controls. Add in a 15 year old car and you have questionable rubber hose integrity. I know on my 93 the vacuum hoses I've had to deal with have been aged pretty badly. Its possible you have a vacuum leak at or from the controller. FWIW. Good luck. 
Larry
Larry
Advanced
Joined: Apr 2007
Posts: 78
Likes: 0
From: OHIO
I have got the same problem with my 94 cpe with HVAC. You have to play with the buttons several times to get to do what you need it to. I checked my hoses (what I could find easily) and found no problem except around the intake which had some brittle lines from heat that I replaced. If you find the problem, let me know. Thanks
Thread Starter
Instructor
Joined: Jan 2005
Posts: 224
Likes: 2
From: Deerfield Beach FL
Like I said, the car is a 15,000 mile original and has never been apart and is in Brand New condition and is 100% original.......I could see this happening on a very high mileage car that has had alot of use. Thanks for the replies so far,,,
Melting Slicks
Joined: Jun 2002
Posts: 2,705
Likes: 30
From: Chesapeake Beach Maryland
2015 C5 of Year Finalist
Drew,
You need to remove the controller from the dash and disassemble it. There are tiny metallic contacts that get corrosion/dirt/whatever on them over time. They need to be cleaned. I used the end of a slightly abrasive ink erasure (old Skool) and it cleaned them up nicely. I then wiped them down with some alcohol on a swab to get any residue off. Reassemble the controller and you should be trouble free.
I think there is a Tech Tip on this topic under the "Other" menu above.
You need to remove the controller from the dash and disassemble it. There are tiny metallic contacts that get corrosion/dirt/whatever on them over time. They need to be cleaned. I used the end of a slightly abrasive ink erasure (old Skool) and it cleaned them up nicely. I then wiped them down with some alcohol on a swab to get any residue off. Reassemble the controller and you should be trouble free.
I think there is a Tech Tip on this topic under the "Other" menu above.
Pro
Joined: Sep 2004
Posts: 505
Likes: 1
From: Guntersville Alabama
Drew,
You need to remove the controller from the dash and disassemble it. There are tiny metallic contacts that get corrosion/dirt/whatever on them over time. They need to be cleaned. I used the end of a slightly abrasive ink erasure (old Skool) and it cleaned them up nicely. I then wiped them down with some alcohol on a swab to get any residue off. Reassemble the controller and you should be trouble free.
I think there is a Tech Tip on this topic under the "Other" menu above.
You need to remove the controller from the dash and disassemble it. There are tiny metallic contacts that get corrosion/dirt/whatever on them over time. They need to be cleaned. I used the end of a slightly abrasive ink erasure (old Skool) and it cleaned them up nicely. I then wiped them down with some alcohol on a swab to get any residue off. Reassemble the controller and you should be trouble free.
I think there is a Tech Tip on this topic under the "Other" menu above.
Thread Starter
Instructor
Joined: Jan 2005
Posts: 224
Likes: 2
From: Deerfield Beach FL
Thank You biggrizzly & 93cruiser.......That does make sence. I have a '78 that I tinker with from time to time........I have never really worked on the '93 at all except for routine maintanence......Not so sure I want to tackle this, is there any step by step instructions posted anywhere I could follow? Thanks again!
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