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Circuit/System Testing

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NOTE: If the evaporator air temperature sensor has an out of range condition caused by a short to voltage, short to ground, or an open/high resistance, the scan tool will display the same value: 11°C (51°F).
  1. Ignition OFF, disconnect the harness connector at the evaporator air temperature sensor.
  2. Ignition OFF, test for less than 10 ohms between the low reference circuit terminal 2 and ground.
    • If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the HVAC control module.
  3. Ignition ON, test for 4.8-5.2 volts between the signal circuit terminal 1 and low reference circuit terminal 2.
    • If less than the specified range, test the signal circuit for a short to ground or open/high resistance. If the circuit tests normal, replace the HVAC control module.
    • If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the HVAC control module.
  4. If all circuits test normal, test or replace the evaporator air temperature sensor.