A/C controls going nuts & erratic idle
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Joined: Aug 2001
Posts: 61
Likes: 15
A/C controls going nuts & erratic idle
I am having two problems with my '88 that may or may not be related (other than being on the same car).
1. The A/C has Electronic Climate Control. The LCD and the indicating lights on the control (i.e., auto, bi-level, econ. defrost) will sometimes go nuts; LCD will rapidly display random patterns and the indicating lights will flash. What is going on here? Also, when I do put A/C on maximum (i.e. 60 deg.), the compressor clutch engages/disengages continuously, is this normal?
2. The idle is erratic. With the A/C off, the idle oscillated from about 600-800 rpm. With the A/C on, it oscillates between about 500-700. The engine has stalled a couple of times.
I am new to C4 vettes, only had it for a couple of days now. Any assistance is greatly appreciated.
1. The A/C has Electronic Climate Control. The LCD and the indicating lights on the control (i.e., auto, bi-level, econ. defrost) will sometimes go nuts; LCD will rapidly display random patterns and the indicating lights will flash. What is going on here? Also, when I do put A/C on maximum (i.e. 60 deg.), the compressor clutch engages/disengages continuously, is this normal?
2. The idle is erratic. With the A/C off, the idle oscillated from about 600-800 rpm. With the A/C on, it oscillates between about 500-700. The engine has stalled a couple of times.
I am new to C4 vettes, only had it for a couple of days now. Any assistance is greatly appreciated.
Racer
Joined: Jul 2001
Posts: 399
Likes: 1
From: Toronto Ontario
Re: A/C controls going nuts & erratic idle (JDF)
My 89 electronic A/C control sometimes "goes crazy" too. I've removed the A/C controller and resoldered all the components. I thought the problem may be cold solder. It obviously isn't. The best short term fix I've found is to give the side of the unit a quick smack with your hand. (no joke)
Does anyone know where I can obtain a schematic diagram and a bill of materials for this electronic A/C controller?
Does anyone know where I can obtain a schematic diagram and a bill of materials for this electronic A/C controller?
Le Mans Master
Joined: Mar 2000
Posts: 9,127
Likes: 2,326
From: Pottsville, PA. USA Home Of America's Oldest Brewery Yuengling
Re: A/C controls going nuts & erratic idle (vette_tweak)
Remove the control from the car and take the two clips that hold the face on off. Take an eraser and clean the contacts on the bottom of the board and most times this will fix it. :smash: :mad :cheers: :chevy
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
Re: A/C controls going nuts & erratic idle (Corvette ED)
Circuit info is available from http://www.batee@umr.edu Low battery voltage will cause the a/c control to go nuts as will poor connector connection. I do not recommend using an eraser on the board connector strips because they are atoms thick gold and an eraser will take the gold off and then you will have nothing BUT trouble. Use an electronic contact cleaner, or alcohol and a cloth.
Pro
Joined: Jun 2000
Posts: 686
Likes: 0
From: Crystal Lake, IL USA
Re: A/C controls going nuts & erratic idle (JDF)
Remove the control from the car and take the two clips that hold the face on off. Take an eraser and clean the contacts on the bottom of the board and most times this will fix it
I had the exact same problem you described with the LCD panel going nuts and none of the buttons responding. I cleaned off the connector as the quote above says and I haven't seen the problem since. I used liberal WD40 on both the board and the socket. May have *lightly* rubbed with an eraser, don't remember.
Your compressor clutch cycling could be due to slightly low Freon. Or it could be normal depending on the ambient temperature. Or the low pressure cutoff switch could be failing. Or the orifice could be partially blocked. Most likely needs topping off with a pound or two of freon.
Idle surge could be several things. First thing to check is how clean is the throttle body and IAC.
I had the exact same problem you described with the LCD panel going nuts and none of the buttons responding. I cleaned off the connector as the quote above says and I haven't seen the problem since. I used liberal WD40 on both the board and the socket. May have *lightly* rubbed with an eraser, don't remember.
Your compressor clutch cycling could be due to slightly low Freon. Or it could be normal depending on the ambient temperature. Or the low pressure cutoff switch could be failing. Or the orifice could be partially blocked. Most likely needs topping off with a pound or two of freon.
Idle surge could be several things. First thing to check is how clean is the throttle body and IAC.
Racer
Joined: Oct 2000
Posts: 383
Likes: 0
From: Moss Point Ms.
Re: A/C controls going nuts & erratic idle (Hendej)
Another possibility is that the car is in diagnostic mode. Mine does this when I plug the diacom software's connector into the ALDL connector to the cars computer. Sometimes it will even turn itself on. I read somewhere that it does that to tell you what problems it's having if you're in diagnostic mode, sort of like the way the computer flashes a certain number of times to give you the trouble codes. Only problem is I don't know how to get it OUT of diagnostic mode, especially if you don't have the car's computer jumpered for it. SOrry not more help.
