I have a 1992 Cadillac Brougham 5.7 liter engine with a R-12 refrigerant ac system, 53,000 miles. The system is fully charged but at idle the compressor will disengage and not start again unless A) I high rev the engine B) tap on the canister molded onto the high pressure hose where the connection for the manifold gauge hose would attach. Am I dealing with a contaminated system? Any advice appreciated.
Sounds like a pressure switch problem. Test for power in and out of the low pressure cycling switch. Sometimes they get weak and wont hold the comp on
July, 16, 2007 AT 8:56 PM
You almost nailed it and without question pointed me to the problem. It wasn't the switch. It was the wire to the switch. At some point it had been misrouted and was rubbing up against the alternator bracket. The insulation wore thin and it was intermittently shorting out to ground causing the compresssor to disengage. I cut out the bad piece of wire and spliced in a new piece and its working great. Thanks so much for the lead.