Ambient Temperature Sensor / Switch HVAC: Testing and Inspection
AMBIENT TEMPERATURE SENSOR DIAGNOSTICSThe outside temperature function is supported by the ambient temperature sensor, a signal and ground circuit hardwired to the compass/temp module, and the Compass/Temp Mirror display.
If the Compass/Temp Mirror display indicates 60 °C (140 °F) or the ambient temperature sensor sense circuit is shorted to ground, the temp display will be 60 °C (140 °F) to indicate a SHORT circuit condition.
If the Compass/Temp Mirror display indicates -45 °C (-49 °F) or the ambient temperature sensor sense circuit is open, the temp display will be -45 °C (-49 °F) to indicate an OPEN circuit condition.
If there is an OPEN or SHORT circuit condition, it must be repaired before the Compass/Temp Mirror VF display can be tested.
The ambient temperature sensor can be diagnosed using the following Sensor Test. If the ambient temperature sensor and the circuits are confirmed to be OK, but the temperature display is inoperative or incorrect, replace the Compass/Temp Mirror.
AMBIENT TEMPERATURE SENSOR TEST
1. Turn the ignition OFF.
2. Disconnect and isolate the battery negative cable.
3. Disconnect the ambient temperature sensor harness connector.
4. Measure the resistance of the ambient temperature sensor using the following values:
AMBIENT TEMPERATURE SENSOR RESISTANCE
0 °C (32 °F) 29.33 - 35.99 Kilohms
10 °C (50 °F) 17.99 - 21.81 Kilohms
20 °C (68 °F) 11.37 - 13.61 Kilohms
25 °C (77 °F) 9.12 - 10.86 Kilohms
30 °C (86 °F) 7.37 - 8.75 Kilohms
40 °C (104 °F) 4.90 - 5.75 Kilohms