Campbelljj

I have an 1989 951 with no power to my compressor (clutch). The system is charged properly and the compressor works fine pressures good (jumped power direct to clutch). Relay, inside switch, DME temp switch all tested/replaced known good. What should I look at next. I am guessing it has something to do with the high pressure switch on the high side by the drier. The hi-pressure switch has four wires - two black/blue and two black. Any help is much appreciated as it is starting to get real hot down here.

griffiths

If its a 4 wire then possibly its a "low-high" switch. Look at the shop schematic in section 97. There were a few rev changes on the condenser to drier hose.

944hal

Very interested in this thread. I have the same problem on an '89 S2. Not an emergency since it's down with a bad clutch (not the AC one). Would like to get the AC fixed for later this summer.

Campbelljj

I tried to poke around with my meter today (to diagnose switch) and of course it decided to bug out now after 15 yrs of perfect use. Go figure! Anyway I pulled the switch p/n 964 613 137 00. Need to try and test or get another.

griffiths

Inspect the clutch. If the coil is fried replace the compressor and clutch.

Campbelljj

Thanks Griffiths. I just jumpered the switch harness and the clutch engages no problem. I also checked continuity on the pressure switch and it failed. My guess is I need another switch. It seems this is the switch from 89 on from what I have researched.

944Ross

Is it the LP or HP side of the switch that is bad? If it's the LP, you could pretty safely jumper it.