Alan

Yes certainly you are right '88 and later have the dual pressure switch - I think '87's actually still have the single low pressure switch.

Alan

dr bob

Mark--

Both the pressure switch and the pressure transducer sit on fittings that have Schraeder valves built in. You can remove and replace either component without losing refrigerant. The pressure transducer controls the fan speed (and the grill flap position if you have them).

IIRC, the wiring diagram for my '89 shows the pressure safety switch with both over- and under-pressure protection.

j.kenzie@sbcglobal.net

I wonder why the dual pressure switches in 88 when I assume they did not switch to r134 until '92 or '93.
I didn't think high pressure safety was critical with r12.
Dave

MBMB

The mystery deepens. Mine is an '89, so should already have the dual pressure switch. I may swap in a new one and see if there is a change.

MBMB

Well, as it turns out this last part, at least, is not necessarily correct.

SeanR

Yeah I'm not so sure why that was said. Everyone that I've done has needed an AC O-ring on the low pressure switch.

j.kenzie@sbcglobal.net

The original a/c drier on my Bentley had a Shrader valve for the pressure switch. The new replacement item did not. My 928 has a pressure switch which does not have a valve, just a threaded hole. The temp switch has a blind threaded hole, it just reads the temp of the metal of the drier.
Good luck,
Dave