The 3-pole switch serves 2 functions - to turn on the fans at high speed at one setpoint and cut the AC compressor at a higher setpoint. If the coolant isnt over 120*C, you've already determined the temp switch to be bad. Did the temp switch get wet recently? They don't like to get wet.

The aux fan low speed is triggered by the temp switch on the dryer. Disconnect and jump the connectors on pigtails to check the low speed function. Disconnect and jump the 2-pin connector on the temp switch to test the high speed function. The fan doesn't necessarily come on because the compressor is engaged.

Sixto
87 300D^2