C4 air cond issue
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Joined: Apr 2003
Posts: 60
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From: Cedar Park TX
C4 air cond issue
Have no a/c, ran fine till Thursday on the way to work. Compressor won't come on, fans don't come on, except if over 228 degrees. No C68 module codes. No flashing LED's on climate control panel.
The interesting thing is that when command AC on, LED lights, inside blower runs, compressor no go and fans no-go, and IAC doesn't rev engine up . Previous system failures (pressure switch connector) had all of the above symptoms, but IAC upped RPM by 100 or so.
It's sleeping in the garage right now, and company from out of town will keep me from this for a week or so, but someone may have encountered this already, why re-invent the wheel? From the manual I'm suspecting pressure switch again, but the idle speed thing not happening this time is making me think its elsewhere. GeorgeC
RED92
The interesting thing is that when command AC on, LED lights, inside blower runs, compressor no go and fans no-go, and IAC doesn't rev engine up . Previous system failures (pressure switch connector) had all of the above symptoms, but IAC upped RPM by 100 or so.
It's sleeping in the garage right now, and company from out of town will keep me from this for a week or so, but someone may have encountered this already, why re-invent the wheel? From the manual I'm suspecting pressure switch again, but the idle speed thing not happening this time is making me think its elsewhere. GeorgeC
RED92
Instructor
Joined: Jun 2008
Posts: 173
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From: Norman OK
Per my 91 FSM, by the lack of RPM increase, the Heater and AC Programmer may be hung. You might disconnect the neg battery terminal for 30 seconds and reconnect to see if it resets.
Also, if the 92 is the same as my 91, check the CTSY fuse in the main fuse panel. It supplies "battery" input to the programmer. The AC fuse supplies Switched IGN voltage.
If not, you may try to jumper the pressure cycling switch connector to see if the compressor runs. If not, then the high pressure switch or AC clutch relay may be suspect.
Also, if the 92 is the same as my 91, check the CTSY fuse in the main fuse panel. It supplies "battery" input to the programmer. The AC fuse supplies Switched IGN voltage.
If not, you may try to jumper the pressure cycling switch connector to see if the compressor runs. If not, then the high pressure switch or AC clutch relay may be suspect.
Le Mans Master
Joined: Dec 2000
Posts: 7,839
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From: San Diego, Ca
Open at the Pressure Cycling or Low Pressure Switch - assuming no (Low Gas) Codes. Usually the connector but I'd check the Switch first to make sure it's closed. If so, wriggle it (the connector) around. Try holding it onto the switch. My truck use to give it up when it had sat at Home Depot for an hour or so when it was 95 plus. Finally spliced in a new connector.
