Coolant Temperature Switch

Air Conditioning Circuit:

PURPOSE
The coolant temperature switch transmits an "A/C ON" signal to the ECM.

LOCATION
The coolant temperature switch is mounted in the thermostat housing.


OPERATION
When the engine coolant temperature is below 239° F, the bimetal strip inside the switch completes the circuit. This allows the ECM to determine if conditions are suitable for A/C operation. When the coolant temperature exceeds 235° F, the bimetal strip inside the switch opens circuit. This prevents the signal from being sent to the ECM.