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Home >> Isuzu >> 2007 >> i-290 LS, Standard >> Repair and Diagnosis >> External Pages >> Different car >> Section 21 (Power Door Lock System And Release Systems) >> Diagnostic Information and Procedures >> Trunk Release Inoperative >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2007 Cadillac DTS. However, it is still accessible from the selected car via links, so may be relevant.

Valet Switch Malfunction

  1. Ignition OFF, disconnect the harness connector at the valet switch.
  2. Test for less than 1.0 ohm of resistance between the ground circuit terminal A and ground.
    • If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify the scan tool Valet Switch parameter is Inactive.
    • If not the specified value, test the signal circuit terminal B for a short to ground. If the circuit tests normal, replace the BCM.
  4. Install a 3A fused jumper wire between the signal circuit terminal B and ground. Verify the scan tool Valet Switch parameter is Active.
    • If not the specified value, test the signal circuit terminal B for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  5. If all circuits test normal, test or replace the valet switch.

Trunk Release Switch Malfunction

  1. Ignition OFF, disconnect the harness connector at the headlamp switch.
  2. Test for less than 1.0 ohm of resistance between the ground circuit terminal 8 and ground.
    • If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify the scan tool Int Trunk Sw 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. Install a 3A fused jumper wire between the signal circuit terminal 10 and ground. Verify the scan tool Int Trunk 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.
  5. If all circuits test normal, test or replace the headlamp switch.

Rear Compartment Lid Latch Malfunction

  1. Ignition OFF, disconnect the TRUNK RELSE relay.
  2. Ignition OFF, test for less than 1.0 ohm of resistance between the ground circuit terminal 143 and ground.
    • If greater than the specified range, test for an open/high resistance.
  3. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal 140 and ground.
    • If the test lamp illuminates, test the control circuit for a short to voltage.
  4. Verify that a test lamp illuminates between the B+ circuit terminal 142 and ground.
    • If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the TRUNK RELSE fuse is open, test the control circuit terminal 140 for a short to ground.
  5. Ignition OFF, disconnect the harness connector at the rear compartment lid latch.
  6. Ignition OFF, test for less than 1.0 ohm of resistance between the rear compartment lid latch ground circuit terminal 3 and ground.
    • If greater than the specified range, test the ground circuit for an open/high resistance.
  7. Connect the harness connector at the rear compartment lid latch.
  8. Ignition ON, connect a 10A fused jumper wire between the B+ circuit terminal 142 and the control circuit terminal 140. Verify the rear compartment lid latch is activated.
    • If the rear compartment lid latch does not activate, test the control circuit for an open/high resistance. If the circuit tests normal, test or replace the rear compartment lid latch.
  9. Connect a test lamp between the control circuit terminal 139 and the ground circuit terminal 143.
  10. Command the Trunk Release 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 voltage. If the circuit tests normal, replace the BCM.
    • If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  11. If all circuits test normal, test or replace the TRUNK RELSE relay.
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