> >-----Original Message-----
> >From: Vanagon Mailing List
> >[mailto:vanagon@gerry.vanagon.com] On Behalf Of Mark Drillock
> >Sent: Monday, September 10, 2007 5:10 PM
> >To: vanagon@GERRY.VANAGON.COM
> >Subject: Re: A/C and High Radiator Fan Questions
> >
> >An 87 with factory air has a 3 speed fan, not a 2. What you
> >are calling high speed may well be medium speed.
> >
> >High speed is only turned on by the radiator temp switch
> >when high radiator temps are sensed.
> >Medium speed is only turned on by the A/C system when the
> >pressure in the hose gets too high.
> >Low speed is controlled by 2 things, either the radiator
> >temp switch lower section or the A/C relay when the A/C is on.

Hi Mark,
Thanks for the input.  I think you are right, that it is the medium speed.
This has happened before when the outside temperature was pretty warm.  The
van has a brand new SVX A/C compressor and recent 134-A charge.  Is this
combination likely to cause the high pressure I am learning about?

I assume the high pressure triggers the higher fan speed to put more air
over the condenser, thus cooling the refrigerant and lowering the pressure.

Is it common that the extra cooling is necessary?  I wonder if the pressure
switch is drifting low.

Thanks again for the help.

Tom