1995 Buick Lesabre

[Mark86]

John for the win. There was a Schrader valve under the switch. I discharged and left about 10 psi in the system. Removed the switch and low and behold there is a Schrader valve hissing at me. I took pick pics of the switch to get part a part number. There was an O-ring on the Schrader body which was torn in half. I put an O-ring from a generic kit on and put the switch back on.

Ordered an AC Delco with same part number, it will be here Sunday.

I wanted to leave some residual pressure in the system, in the hopes of not needing to vacuum it down. If I replace that Schrader valve that will empty the system. I’m guessing this will be the last fan switch this car ever sees, so thinking of just installing new switch and let it be.

[JohnHere]

I wanted to leave some residual pressure in the system, in the hopes of not needing to vacuum it down. If I replace that Schrader valve that will empty the system. I’m guessing this will be the last fan switch this car ever sees, so thinking of just installing new switch and let it be.

Good idea. If you replace the switch quickly enough, you should still have some pressure left in the system, which will eliminate the necessity of evacuating the system again.

[Mark86]

New switch is in and system recharged. Was unable to obtain a 210 psi on the high side to determine if the new switch signals the fans to “high”. Apparently that part number serves three switches, and the first one I ordered albeit identical in all regards, would not accept the electrical connector plug on the vehicle harness.

[tbirdtbird]

This has been such a long thread I can't recall everything.
Was the idea of just hard wiring the high speed fan directly to "compressor on", thus giving the comp the high speed fan at all times?