Operation CHARM: Car repair manuals for everyone.

In-Car Temperature Sensor Test

In-car Temperature Sensor Test

1. Remove the in-car temperature sensor.
2. Compare the resistance reading between the No. 2 and No. 3 terminals of the in-car temperature sensor with the specifications shown in the graph; the resistance should be within the specifications for whatever the ambient temperature is.






3. If the resistance is not as specified, replace the in-car temperature sensor.

NOTICE:
Incorrectly applying power and ground to the in-car temperature sensor will damage it. Follow the instructions carefully.

4. Connect battery power to the No. 1 terminal of the in-car temperature sensor, and ground the No. 4 terminal; the aspirator fan should run.
5. If the aspirator fan did not run in step 4, replace it.