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Home >> Chevrolet >> 2020 >> Express 2500 LS, 6.0L Eng VIN G >> Repair and Diagnosis >> External Pages >> Different car >> Section 79 (HVAC - Manual) >> Diagnostic Information and Procedures >> Air Temperature Malfunction >> Circuit/System Testing

Circuit/System Testing

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  1. Ignition OFF, disconnect the harness connector at the air temperature actuator.
  2. Test for less than 1.0 ohm between the ground circuit terminal 7 and ground.
    • If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal 10 and ground.
    • If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance.
  4. Install a DMM between the control circuit terminal 8 and ground. Command the actuator in both directions. Voltage on the control circuit should change from 0 volts when commanding the actuator in one direction to 12 volts in the other direction.
    • If the voltage does not change as specified, test the control circuit for a short to voltage, short to ground, or an open/high resistance. If the circuit tests normal, replace the HVAC control module.
  5. If all circuits test normal, test or replace the air temperature actuator.
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