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Home >> GMC >> 2022 >> Hummer EV >> Repair and Diagnosis >> Electrical >> Charging Systems >> Plug-In Charging System >> Diagnostic Information and Procedures >> Plug-In Charging Indicator Malfunction >> Circuit/System Testing
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Circuit/System Testing

  1. Vehicle OFF, disconnect the harness connector at the E85 Charge Port Housing Lamp.
  2. Test for less than 10 Ω between the low reference terminal 1 and ground.
    • If 10 Ω or greater 

      Repair the open/high resistance in the circuit.

    • Go to next step: If less than 10 Ω 
    3. NOTE:

    If the drive motor battery charger cable is connected. The drive motor battery charger cable must be disconnected for more than 10 s before performing the next step.

  3. Vehicle OFF. Connect a test lamp between the B+ terminal 2 and ground.
  4. Vehicle On. Verify the test lamp illuminates.
    • If the test lamp does not illuminate 
    1. Check for a open fuse.
      • If the fuse is open

        Check for less than infinite resistance between circuit and ground.

      • If less than infinite resistance
      • Repair the short to ground on the circuit.
      • Go to next step: If infinite resistance
    2. Replace the E85 Charge Port Housing Lamp
      • If the fuse is not blown
      • Repair open/high resistance on the circuit.
      • Go to next step: If open/high resistance is not found
    3. Replace the E85 Charge Port Housing Lamp
    • Go to next step: If the test lamp illuminates 
  5. Vehicle ON. Test for between 3.5-12V between the LIN serial data circuit terminal 3 and ground.
    • If less than 3.5 V
    1. Vehicle OFF. Disconnect the X6 harness connector at the K9 Body Control Module.
    2. Test for infinite resistance between the LIN serial data circuit terminal and ground.
      • If less than infinite resistance - Repair the short to ground on the circuit.
      • Go to next step: If infinite resistance
    3. Test for less than 2 ohms in the LIN serial data circuit end to end.
      • If 2 ohms or greater - Repair the open/high resistance in the circuit.
      • Go to next step: If 2 ohms or less
    4. K9 Body Control Module - Replace
    • If greater than 12 V
    1. Vehicle OFF. Disconnect the X6 harness connector at the K9 Body Control Module.
    2. Vehicle ON. Test for less than 1 V between the LIN serial data circuit terminal and ground.
      • If 1 V or greater - Repair the short to voltage on the circuit.
      • Go to next step: If 1 V or less
    3. K9 Body Control Module - Replace
    • If between 3.5 and 12 V
  6. Vehicle OFF. Inspect both harness and component connectors for contamination, corrosion, and terminal tension.
  7. Reconnect the harness connector at the E85 Charge Port Housing Lamp. Verify all connectors/terminals are fully seated.
  8. Re-preform the Circuit/System Verification.
    • If the vehicle charge indicator is still not operating properly 
    • E85 Charge Port Housing Lamp - Replace
    • Go to next step: If the vehicle charge indicator is now operating properly 
  9. All OK.
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