c4 a/c not working
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Heel & Toe
Joined: Dec 2010
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c4 a/c not working
A/C not working,checked climate control diagnostic coded #9 I found low refrigerant,checked with gauges had 120 lbs. static pressure,bypassed low pressure switch still would not engauge the compressor clutch. No power to compresser. Maybe the climate control head? Any help please. puma421
Melting Slicks
Joined: Aug 1999
Posts: 2,240
Likes: 42
From: Baltimore, MD USA
A/C not working,checked climate control diagnostic coded #9 I found low refrigerant,checked with gauges had 120 lbs. static pressure,bypassed low pressure switch still would not engauge the compressor clutch. No power to compresser. Maybe the climate control head? Any help please. puma421
You need to disconnect and reconnect the negative battery cable to reset the AC Programmer.
Race Director
Joined: Apr 2002
Posts: 10,036
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From: Anaheim CA
A/C not working,checked climate control diagnostic coded #9 I found low refrigerant,checked with gauges had 120 lbs. static pressure,bypassed low pressure switch still would not engauge the compressor clutch. No power to compresser. Maybe the climate control head? Any help please. puma421
Melting Slicks
Joined: Jun 1999
Posts: 2,931
Likes: 127
From: Ashland Alabama
You didn't say what year your car is so Im going to guess its around the year of my old 86.
Are you sure you shorted the low side switch?
This shows the 2 switches and which one is which.
http://crowz.narmir.com/corvette/aircondi.htm
Always start with a check of fuses.
As for diagnosing a/c clutch engagement start with the compressor clutch first. These can go bad completely or they can wear down to the point they aren't strong enough to engage anymore. Make sure you have 12 volts positive and ground at the compressor clutch plug itself. Simple voltmeter test for that one. If there is 12 volts present with the a/c set to on the clutch is bad. If there isn't power there then worry about the low pressure switch. If the clutch is good, low pressure switch is ok, and fuse is ok then its the head unit part.
I have all the diagrams for the type that's in the 84-89 c4 for the climate control stuff if it turns out to be that.
Are you sure you shorted the low side switch?
This shows the 2 switches and which one is which.
http://crowz.narmir.com/corvette/aircondi.htm
Always start with a check of fuses.
As for diagnosing a/c clutch engagement start with the compressor clutch first. These can go bad completely or they can wear down to the point they aren't strong enough to engage anymore. Make sure you have 12 volts positive and ground at the compressor clutch plug itself. Simple voltmeter test for that one. If there is 12 volts present with the a/c set to on the clutch is bad. If there isn't power there then worry about the low pressure switch. If the clutch is good, low pressure switch is ok, and fuse is ok then its the head unit part.
I have all the diagrams for the type that's in the 84-89 c4 for the climate control stuff if it turns out to be that.
