Circuit/System Testing

2007 Cadillac XLR BaseSECTION Circuit/System Testing

Console Courtesy Lamp Malfunction

  1. Ignition OFF, disconnect the harness connector at the console courtesy lamp.
  2. With the console open, test for less than 1 ohm of resistance between the switched ground circuit terminal B and ground.
    • If greater than the specified range, test the ground circuit for an open/high resistance, if the circuits test normal, replace the console lamp switch.
  3. Ignition ON, verify that a test lamp illuminates between the courtesy lamp supply voltage circuit terminal A and ground.
    • If the test lamp does not illuminate, test the courtesy lamp supply voltage circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  4. If all circuits test normal, replace the console courtesy lamp.

Dome Lamp Switch Malfunction

  1. Ignition OFF, disconnect the harness connector at the driver information center (DIC) switch.
  2. Test for less than 1 ohm of resistance between the ground circuit terminal 7 and ground.
    • If greater than the specified range, test the ground circuit for an open/high resistance. If the circuit tests normal, replace the IPC.
  3. Ignition ON, verify the scan tool dome lamp switch parameter is OFF.
    • If not the specified value, test the signal circuit terminal 4 for a short to ground. If the circuit tests normal, replace the IPC.
  4. Install a 3A fused jumper wire between the signal circuit terminal 4 and ground. Verify the scan tool dome lamp switch parameter is ON.
    • 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 IPC.
  5. If all circuits test normal, test or replace the driver information center (DIC) switch.

Door Courtesy Lamps Malfunction

  1. Ignition OFF, disconnect the harness connector at the inoperative door courtesy lamp.
  2. Test for less than 1 ohm of resistance between the ground circuit terminal 2 and ground.
    • If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Connect a test lamp between the control circuit terminal 1 and the ground circuit terminal 2.
  4. Command the inoperative door exterior courtesy lamp 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 appropriate door control module.
    • 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 appropriate door control module.
  5. If all circuits test normal, replace the inoperative door courtesy lamp.

Door Open Switch Malfunction

  1. Ignition OFF, disconnect the harness connector at the inoperative door latch assembly.
  2. Test for less than 1 ohm of resistance between the ground circuit and ground.
    • If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify the scan tool door open switch parameter is KEY OFF.
    • If the scan tool displays DOOR OPEN, test the signal circuit for a short to ground. If the circuit tests normal, replace the BCM.
  4. Install a 3A fused jumper wire between the signal circuit and ground. Verify the scan tool door open switch parameter is DOOR OPEN.
    • 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 inoperative door latch assembly.

Instrument Panel (I/P) Compartment Lamp Malfunction

  1. Ignition OFF, disconnect the harness connector at the I/P compartment lamp.
  2. Test for less than 1 ohm of resistance between the ground circuit terminal B 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 courtesy lamp supply voltage circuit terminal A and ground.
    • If the test lamp does not illuminate, test the courtesy lamp supply voltage circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  4. If all circuits test normal, replace the I/P compartment lamp switch.

Instrument Panel Courtesy Lamps Malfunction

  1. Ignition OFF, disconnect the harness connector at the inoperative courtesy lamp.
  2. Test for less than 1 ohm of resistance between the low control circuit terminal B and ground.
    • If greater than the specified range, test the low control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  3. Ignition ON, verify that a test lamp illuminates between the courtesy lamp supply voltage circuit terminal A and ground.
    • If the test lamp does not illuminate, test the courtesy lamp supply voltage circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  4. Ignition OFF, connect a test lamp between the supply voltage circuit terminal A and the low control circuit terminal B.
  5. Command the interior lamps on with a scan tool. The test lamp should turn ON for 5 seconds and then turn OFF.
    • If the test lamp remains ON at all times, test the low control circuit for a short to ground. If the circuits test normal, replace the BCM.
  6. If all circuits test normal, replace the inoperative courtesy lamp.

Rear Compartment Courtesy Lamps Malfunction

  1. Ignition OFF, disconnect the harness connector at the inoperative rear compartment lamp.
  2. Open the rear compartment lid.
  3. Test for less than 1 ohm of resistance between the ground circuit terminal B and ground.
    • If greater than the specified range, test the ground circuit for an open/high resistance, if the circuits test normal, replace the rear compartment lid latch or pull down actuator.
  4. Ignition ON, verify that a test lamp illuminates between the courtesy lamp supply voltage circuit terminal A and ground.
    • If the test lamp does not illuminate, test the courtesy lamp supply voltage circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  5. If all circuits test normal, replace the inoperative rear compartment lamp.

Underhood Lamp Malfunction

  1. Ignition OFF, disconnect the harness connector at the underhood lamp.
  2. Test for less than 1 ohm of resistance between the ground circuit terminal B 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 courtesy lamp supply voltage circuit terminal A and ground.
    • If the test lamp does not illuminate, test the courtesy lamp supply voltage circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  4. If all circuits test normal, replace the underhood lamp.

Vanity Mirror Lamps Malfunction

  1. Ignition OFF, disconnect the harness connector at the inoperative vanity mirror.
  2. Test for less than 1 ohm of resistance between the ground circuit terminal B 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 courtesy lamp supply voltage circuit terminal A and ground.
    • If the test lamp does not illuminate, test the courtesy lamp supply voltage circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  4. If all circuits test normal, replace the inoperative vanity mirror.
RENDER: 1.0x

NO RELATED

Recommended Tools & Savings

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

Affiliate disclosure: We may earn a commission at no extra cost to you.

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.