Thought problem was in either the a/c clutch relay or the ac relay. After
checking the ac relay I find that there is electricity going in and
electricity coming out through the red black wire. This wire goes to a sensor
that is connected to one of the coolant lines. It is not in the Bentley, but
appears to have replaced the hi and lo pressure switches that are pictured in
Bentley. Four wires to this cylindrical sensor and only one has current.

Moving backwards - found no current to ac clutch - a red blue wire. Nothing
at any of the four posts on the clutch relay. No power at the ambient temp
switch or the ac thermostat. The wiring diagram seems to point to the ac
pressure switch - which again I assume is the cylindrical thing mentioned
above.

Anyone had this problem? and will I be loosing freon as I change out this
switch?
Ref wiring diagram page 97.144 in Bentley labeled f129 ac press sw.
Vehicle is 91 Carat - freon recharged in June - problem was intermittent as
per earlier post. Made me think it was a defective relay.

Thanks
Tom Callan
91 Carat