Radiator Cooling Fan Temperature Sensor / Switch: Description and Operation

OPERATION
The contact between terminals "A" and "B" is normally open.

The contact is closed at 325 psi and the engine cooling fan motor will run at high speed.

The contact will reopen at 275 psi. The engine cooling fan motor will run for approximately 20 seconds after the contact has reopened to ensure that when the A/C compressor turns back ON.

The contact between terminals "C" and "D" is normally closed. The contact opens at 425 psi, shutting OFF the A/C compressor.

When the pressure falls to 250 psi, the contacts close and allow A/C compressor operation.