With engine running and turning A/C on will turn the compressor clutch ON and immediately OFF again. Thereafter nothing will happen. Condensor fan however turns on and stays on. Pressure switch on drier is good. Jumping pressure switch will not engage the clutch. Pressure on low side reads 110 PSI with engine running i.e pressure switch is closed. Turning engine off and on again after a minute and do above process again will result in the same quick On/Off of the compressor clutch.
Can anybody enlighten me where possibly the problem could be? Is there a relay somewhere that is the culptit?
Your input will be appreciated.
Paul

Your getting 110 psi on the low side, with the engine running and the compressor is not running? Just trying to be sure I understand you correctly.

If you can check your static low side pressure again, engine off and at ambient temp. (cold). At ~72F the low side should read about 75 psi, STATIC.

DEWFPO
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1998 S90 077,400 and 1995 964 154,100

DEWFPO, you are understanding correctly. I get today a static low side pressure of about 100psi with the engine off. No difference actually when engine runs or not. The clutch only comes in momentarely (less than a second) and then stays off.
System was working fine until this started to happen.
There is 12V at the pressure switch connector. Is there another relay somewhere that is not operating? Similarly as those used to run the condensor fan? It is difficult to figure things out electrically without a schematic.
If there is a relay where would I find it.
Thanks, Paul

Was the engine hot when you tested the static pressure? Was it 100F out side? 100 psi static is high.

I have a 95 and it has 3 pressure sensors on the condenser, our 98 only has only one. I don't know how many the 96 has. The fan is controlled by engine temp and A/C system pressures.

DEWFPO
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1998 S90 077,400 and 1995 964 154,100

Most times when someone has this, the refrigerant is low. You may have a leak somewhere.

DanR '94 964 334,000 miles (100,000 on the new engine)
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DanR