Cabin Temperature Sensor / Switch: Testing and Inspection

DIAGNOSIS AND TESTING - IN-CAR TEMPERATURE SENSOR

NOTE: For complete circuit diagrams, see Wiring Information. Wiring Information includes wiring diagrams, connector pin-out and location views, details of wire harness routing and retention, splice and ground locations and proper wire and connector repair procedures.

Using a scan tool, check for Diagnostic Trouble Codes (DTCs) related to the in-car temperature sensor and the A/C heater module. If any DTCs are found, repair as necessary Testing and Inspection. If no DTCs are found, perform the two following tests. Replace the in-car temperature sensor if the sensor fails either test.

ASPIRATOR MOTOR TEST

The in-car temperature sensor uses an aspirator motor to draw air from the passenger compartment and flow the air over the temperature thermistor. Test the motor as follows.





1. Place the ignition in the Run position.
2. Place a small piece of newspaper in front of the aspirator motor opening grille (1), located on the steering column opening cover (2). If the paper sticks to the grille, the aspirator motor is operating properly. The piece of paper should be only large enough to cover the opening.
3. If the paper does not stick to the grille, check the in-car temperature sensor electrical connections and wiring. If connections and wiring are OK, replace the in-car temperature sensor.

TEMPERATURE THERMISTOR TEST

The in-car temperature sensor uses a temperature thermistor to provide resistance values that correlate with temperature change. Test the thermistor as follows.

1. Remove the in-car temperature sensor and place it on a workbench Front In-Car Temperature Sensor - Removal.
2. Note the current ambient air temperature of the work area.
3. Use an ohm meter and check the resistance between pins 1 and 2 of the in-car temperature sensor. Compare the temperature of the work area to the found resistance value. The resistance should be within specifications as listed in the Resistance and Temperature chart. If not OK, replace the in-car temperature sensor.
RESISTANCE AND TEMPERATURE