Evaporator Temperature Sensor / Switch: Testing and Inspection
EVAPORATOR FIN SENSORThe work area and vehicle must be between 16 °C (60 °F) and 32 °C (90 °F) when testing the switch.
1. Disconnect the three wire connector from the evaporator fin sensor lead located behind the glove box.
2. Start engine and set A/C to low blower motor speed, panel, full cool, and RECIRC.
3. Using a voltmeter, check for battery voltage between Pin 1 and 2. If no voltage is detected, there is no power to the switch. Check wiring and fuses. Refer to the appropriate wiring information. The wiring information includes wiring diagrams, proper wire and connector repair procedures, details of wire harness routing and retention, connector pin-out information and location views for the various wire harness connectors, splices and grounds.
Fig.1 HVAC Controls:
4. Using a voltmeter, check for battery voltage between Pin 1 and Pin 3. If no voltage is detected, there is no voltage from the Powertrain Control Module. Refer to the appropriate wiring information. The wiring information includes wiring diagrams, proper wire and connector repair procedures, details of wire harness routing and retention, connector pin-out information and location views for the various wire harness connectors, splices and grounds. If voltage is OK, connect a jumper wire between Pin 1 and Pin 3. The compressor clutch should engage. If the clutch engages, remove the jumper wire immediately and go to Step 5. If the compressor clutch does not engage, check the operation of the clutch and repair as necessary.
5. If compressor clutch engages, connect the evaporator fin sensor 3-way connector. The compressor clutch should engage or cycle depending on evaporator temperature. If OK, go to Step 6. If not OK, replace the clutch cycling switch.
6. The engine running and the A/C set to:
- Blower motor on low speed
- Panel position
- Full cool
- RECIRC.
Close all doors and windows. Place a thermometer in the center discharge vent.
Fig.14 Evaporator Fin Sensor Harness Connector:
7. If the clutch does not begin to cycle off between 2 °C to 7 °C (35 °F to 45 °F), verify that the evaporator fin sensor is fully installed and not loose in evaporator. If it is not properly installed, install sensor and retest outlet temperature. If the evaporator fin sensor is properly installed, replace the clutch cycling switch.