The AC is a completely separate system from the heater and vent sliders.
It is a purely recirculating system with separate fans in the back.
   Look for two knobs, one with a snowflake symbol.  One sets the fan
speed, the other the desired temperature.  With the engine running and the
fan speed set to "2", turning the temp knob to the right should start the
system and you should hear the front radiator fan come on low speed.  Air
should also come out of the AC unit at the rear of the van due to the
action of those fans.

If these things don't happen, there are many different possible reasons.
When you say it has freon do you mean that you measured the pressure?  If
it is too low, the system will be shut down to protect the compressor.  It
does not get enough lubricating oil if the refrigerant is too low.
  The other obvious suspects would be fuses.  Most fuses are below the left
end of the dash, but the AC also has a fusable link mounted near the AC
relays, etc. in the rear.  I am not familiar with the AC in a late model
Westy, but I would expect these important parts to be hidden in some
cabinetry in the rear on the left side.
   Do you have an operator's manual and/or a Bentley manual?  You need them
both.

Larry A.

On Wed, Jun 29, 2016 at 3:07 AM, Gordon Mah <gordonmahung@gmail.com> wrote:

> Just bought me a 1989 Westy and I can't figure out how to get the air
> conditioning to work.  It has freon.  I tried all the knobs and vent
> sliders and all I get is either heat or just air from the outside.  Does
> anyone know the secret combination of sliders and their positions to make
> this baby keep me cool on such hot days?
>
> Thanks!
>