I'm having problems with the AC & cooling systems on my 90 Westy, and
I'm hoping you can give me some insight into solving them.  First off,
my new-to-me van didn't blow cool air when the AC was on, so I added
some freon and it blows cool now (I'm lucky to have an AC tech as a
friend...alas, he doesn't work on cars, but has the stuff to charge
it).  BUT, running the AC raises the temp of the engine, causing an
EXTEMELY LOUD fan to come on for several minutes while at the same time
causing the compressor to cut off (still blows air, but not cold) during
the duration of the loud fan's operation.  This happens very quickly
around town and I thought that perhaps highway driving wouldn't cause
the temp to raise, but it does, although it goes up very slowly.

So my AC tech friend and I get out the Bentley Manual and start trying
to figure it out.  We remove the spare and check to see that the fan
works.  With the engine running and the AC ON, the fan is not running,
but is getting no DC volts (according to is voltmeter).  The fan blades
spin, the fuses are good, and the windings on the fan motor ohmed out,
showing that they were good.  So we conclude that the fan should work
(and since I can only find one fan stuffed up in there and the loud fan
comes on from time to time, I surmise it does work).

How many stages of operation does the radiator fan have?  On page 19.5,
it shows thermoswitches for stage I and II, and on page 87.3 it shows a
"radiator cooling fan relay, 2nd stage" (#10) and a "radiator cooling
fan relay, 3rd stage".  So how many stages are there and could anyone
describe these stages to me, so I know what to look for?

Could it be the thermoswitche(s)?  if so, how do I test them?  How do I
check the relays mentioned on page 87.3 with a meter (my AC tech wants
to know how to do a "no volt check" as well as what the check points
would be for a volt check?  What else should I check?    Also, can the
fan be wired to a toggle on the van, or is this an easy problem to fix?

TIA!

Ian
--

Ian Webb
ianwebb@rbnet.com