Should be simple enough John, at least on a vanagon with not many system
complexities.

Just unplug the connector that sits on top of the compressor and with the
switch on, check that you are getting power to the connector. Whether you
are or not, as a data point, clip a jumper between the hot side of the
connector half that belongs to the compressor side and the POS terminal of
the battery. Put another jumper between the NEG battery and the case of the
compressor.

It may have been mentioned but one thing you might consider is that if the
refrigerant pressure is too low, there is a switch that will kill the
circuit to the compressor so it won't run even if there is power from the
switch. This is so the compressor won't be ruined if running too low on
refrigerant. So, if everything else (fuses, etc) look good, and the
compressor engages when jumpered (you will hear it click even if not
running) then you will likely want to check out the pressure or the
condition of the pressure switch. I don't think the Vanagon has this
feature, but I had an old Jetta that would not cool when a temp sensor
(that was there to keep the system from accidentally being turned on when
the ambient temp was below freezing) failed. You have to consider those
sensors.

Jim

On Tue, Sep 6, 2016 at 9:45 PM John Rodgers <jrodgers113@gmail.com> wrote:

> I want to check that the clutch does in fact, operate. I should be able to
> put power just to the clutch to see if it engages. This should be doable
> with engine and compressor off. But I don't really know how.
>
> John
>
> On Sep 6, 2016 19:25, "Dan N" <dn92610@gmail.com> wrote:
>
> I have a '88 Carat and the AC works fine for 2 years then one day it stops
> working and work again - sort of cycling... compressor not engaging.. I
> changed the temp knob just to be sure and check all the fuses.. it worked
> for few days and then stops and works again.. intermittent symptom... one
> day check all the connectors at the rear pillar and suddenly the compressor
> engages again.. I cleaned up that connector, make it tight and it works
> good since then
>