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Home >> Hummer >> 2008 >> H2 4D Utility Wagon >> Repair and Diagnosis >> External Pages >> Different car >> Section 493 (HVAC System - Automatic) >> Diagnostic Information and Procedures >> DTC P0645 >> Component Testing

Component Testing

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  1. Ignition OFF, disconnect the A/C COMP relay.
  2. Test for 60-180 ohms between terminals 85 and 86.
    • If the resistance is not within the specified range, replace the relay.
  3. Test for infinite resistance between the following terminals:
    • 30 and 86
    • 30 and 87
    • 30 and 85
    • 85 and 87
    • If not the specified value, replace the relay.
  4. Install a 30-amp fused jumper wire between relay terminal 85 and 12 volts. Install a jumper wire between relay terminal 86 and ground. Test for less than 2 ohms between terminals 30 and 87.
    • If greater than the specified range, replace the relay.