Two cars, two problems.
1. 82 300D that cools when car first starts, then after engine warms it blows warm/hot air even though the compressor is running and trying to cool. So far I have:
Disconnected the circulating pump - reduces the heating but does not eliminate it.
Next tried substituting parts from a part-out 1982 on which air worked prior to parting. Substituted push button unit, control box, dash and plenum sensors, installed new mono valve insert, exchanged the electro-magnet around mono valve. Have checked all five electric/vac valves. After all this the problem persists. I am starting to run out of ideas - for some reason something is telling the sytem to send heat.
The second problem is a car with a Nippon-Denso compressor with centrifugal sensor. I suspect the relay, can anyone tell me which pins on the relay that can be jumped to by-pass the sensor. I have done it in the past but loaned out my A/C manual with the schematic and my notes. Using a jumper from the battery, the compressor runs continually - I believe the relay can be jumped to by-pass the switch in the relay and in doing so the system will cycle normally but the protection is lost.
Thanks for your help.