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Circuit/System Testing

WARNING:

The high intensity discharge system produces high voltage and current. To reduce the risk of severe shocks and burns:

  • Never open the high intensity discharge system ballast or the arc tube assembly starter.
  • Never probe between the high intensity discharge system ballast output connector and the arc tube assembly.

Headlamp Switch Malfunction

  1. Ignition OFF, disconnect the harness connector at the headlamp switch.
  2. Ignition OFF, verify that a test lamp illuminates between B+ and the ground circuit terminal 8.
    • If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
  3. Ignition ON, park lamps ON, verify the scan tool Headlamp Switch parameter is Inactive.
    • If not the specified value, test the signal circuit terminal 1 for short to ground. If the circuit tests normal, replace the BCM.
  4. Verify the scan tool Auto Hdlp. Disable Sw. parameter is Inactive.
    • If not the specified value, test the signal circuit terminal 3 for short to ground. If the circuit tests normal, replace the BCM.
  5. Install a 3 A fused jumper wire between the signal circuit terminal 1 and ground. Verify the scan tool Headlamp Switch parameter is Active.
    • If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  6. Install a 3 A fused jumper wire between the signal circuit terminal 3 and ground. Verify the scan tool Auto Hdlp. Disable Sw. parameter is Active.
    • If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  7. If all circuits test normal, test or replace the headlamp switch.

Turn Signal/Multifunction Switch Malfunction

  1. Ignition OFF, disconnect the X2 harness connector at the turn signal/multifunction switch.
  2. Ignition OFF, verify that a test lamp illuminates between B+ and the ground circuit terminal 8.
    • If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
  3. Verify the scan tool Flash to Pass Switch parameter is Inactive.
    • If not the specified value, test the signal circuit terminal 10 for a short to ground. If the circuit tests normal, replace the BCM.
  4. Verify the scan tool High Beam Select Switch parameter is Inactive.
    • If not the specified value, test the signal circuit terminal 7 for a short to ground. If the circuit tests normal, replace the BCM.
  5. Install a 3 A fused jumper wire between the signal circuit terminal 10 and ground. Verify the scan tool Flash to Pass Switch parameter is Active.
    • If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  6. Install a 3 A fused jumper wire between the signal circuit terminal 7 and ground. Verify the scan tool High Beam Select Switch parameter is Active.
    • If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  7. If all circuits test normal, test or replace the turn signal/multifunction switch.

Headlamps Malfunction - Low Beam

  1. Ignition OFF, disconnect the HID/LO BEAM relay.
  2. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal 87 and ground.
    • If the test lamp illuminates, test the control circuit for a short to voltage.
  3. Verify that a test lamp illuminates between the B+ circuit terminal 85 and ground.
    • If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  4. Verify that a test lamp illuminates between the B+ circuit terminal 30 and ground.
    • If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.
  5. Disconnect the harness connector at the appropriate headlamp - low beam.
  6. Test for less than 5 Ω between the appropriate ground circuit terminal listed below and ground:
    • Without W49/TVD and with WDA/X88 - terminal A
    • Without W49/TVD and with Z88 - terminal B
    • With W49/TVD - terminal 6
    • If greater than the specified range, test the ground circuit for an open/high resistance.
  7. Connect the harness connector at the headlamp - low beam.
  8. Connect a 10 A fused jumper wire between the B+ circuit terminal 30 and the control circuit terminal 87. Verify the headlamp - low beam is activated.
    • If the headlamp - low beam does not activate and the circuit fuse is good, test the control circuit for an open/high resistance. If the circuit tests normal, test or replace the appropriate headlamp - low beam.
    • If the headlamp - low beam does not activate and the circuit fuse is open, test the control circuit for a short to ground. If the circuit tests normal, test or replace the appropriate headlamp - low beam.
  9. Connect a test lamp between the B+ circuit terminal 85 and the control circuit terminal 86.
  10. Command the Low Beams ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
    • If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the BCM.
    • If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  11. If all circuits test normal, test or replace the HID/LO BEAM relay.

Headlamps Malfunction - High Beam

  1. Ignition OFF, disconnect the HI BEAM relay.
  2. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal 87 and ground.
    • If the test lamp illuminates, test the control circuit for a short to voltage.
  3. Verify that a test lamp illuminates between the B+ circuit terminal 85 and ground.
    • If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  4. Verify that a test lamp illuminates between the B+ circuit terminal 30 and ground.
    • If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.
  5. Disconnect the harness connector at the appropriate headlamp - high beam.
  6. Test for less than 5 Ω between the ground circuit terminal listed below and ground:
    • Without W49/TVD - Terminal A
    • With TVD/W49 - Terminal 1
    • With TVD/WDA - Terminal 3
    • With TVD/Z88 - Terminal I
    • With TSH/T26 - Terminal E - Left
    • With TSH/T26 - Terminal P - Right
    • If greater than the specified range, test the ground circuit for an open/high resistance.
  7. Connect the harness connector at the headlamp - high beam.
  8. Connect a 20 A fused jumper wire between the B+ circuit terminal 30 and the control circuit terminal 87. Verify the headlamp - high beam is activated.
    • If the headlamp - high beam does not activate and the circuit fuse is good, test the control circuit for an open/high resistance. If the circuit tests normal, test or replace the appropriate headlamp - high beam.
    • If the headlamp - high beam does not activate and the circuit fuse is open, test the control circuit for short to ground. If the circuit tests normal, test or replace the appropriate headlamp - high beam.
  9. Connect a test lamp between the B+ circuit terminal 85 and the control circuit terminal 86.
  10. Command the High Beams ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
    • If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the BCM.
    • If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  11. If all circuits test normal, test or replace the HI BEAM relay.
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