That latter switch is often known as a "Trinary" switch. It combines low and high pressure safety and high speed fan operation.

Dennis

----- Original Message -----
From: John Bange <jbange@GMAIL.COM>
Date: Thursday, July 20, 2006 12:55 pm
Subject: Re: Newly operational AC just died...

> >  There is probably a low pressure cut off switch that saves the
> > compressor from burning up when the 134a gets low. In post 86
> vanagons,> this is up above the engine area. It has wires attached
> to it. There is
> > also a high pressure cut out switch. Dont know 2.1 vanagons(even
> with a
> > subie) too well. You can remove the electrical connector from
> the low
> > pressure cut off switch9see Bentley)
>
>
> One little "gotcha" in the Bentley is that it shows separate high
> and low
> pressure switches, but on later models (at least on my '90) it's a
> singlecombination switch with four wires coming out and going to a
> flat four pin
> connector. Whichever it is, to test if it's a low pressure sense
> issue you
> can disconnect the pressure switch(es) and jumper the Red-with-
> White-stripe
> and Red-with-Black-stripe wires with the AC turned on. If the
> compressorclutch clicks in, it's a low pressure switch issue of
> some sort. This could
> mean actual low pressure or a bad switch, though.
>
> --
> John Bange
> '90 Vanagon - "Geldsauger"
>