There is a low temp switch in the rear pillar with the A/C wiring. It
keeps the A/C compressor from running whenever the temp is down around
freezing or below. I speculate it is there to prevent freon leaks. When
the weather is very cold, the seals and o-rings in the freon system may
shrink and allow leaks if the compressor runs and the freon pressure
rises.

Mark

John Connolly wrote:
>
> I believe there's a high and low pressure switch (separate switches) behind
> the rear left panel
> (next to the High pressure port), on my 87.
>
> this also jibes with my experience (failure) of my system. I had mixed 134
> and 12, and this clogged the expansion valve. In my 87', once you turned the
> AC on, the pressure backed up on the high side, and triggerred the high
> speed fan. If you shut the van off, the fan would run until the battery died
> (8-10 hours). This is obviously not a high temp switch, if it was temp, it
> would shut off again when the temp dropped. When I replaced the expansion
> valve, flushed the system, and re-charged, everything operates normally
> (including the high speed fan switch).
>
> Maybe there is a high temp switch also?
>
> John