87 C4 a/c compressor relay location??
03-13-2008, 03:08 PM
#3
Heel & Toe
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It is a manual setup. I show 12 volts at the pressure switch and the plug into the compressor. It will not engage. If I jump direct from the battery when the car is not running the clutch locks up? Thanks, Tom
03-13-2008, 03:44 PM
#4
Le Mans Master
Manual circuit is from the a/c fuse to the Dash Controls, out to the High Pressure Cutoff Switch, on to the Low Pressure Switch and on to the Compressor Clutch, then ground. If there's voltage at the Low Pressure Switch, the switch contacts are open. They should be closed with nothing running, even if there's only a 1/2 lb of gas in it - check it with a DVM. If it's an open circuit, it's either out of gas or the switch is bad. Contacts are closed with 50 psi (and as just stated, even a minimal amount gas will give it that when it's sitting doing nothing) - they open at 25 psi, and if were low on gas, the compressor would be cycling on and off - fairly rapidly if it's really low. The only way to find out for your Year is with a manifold gage set.
