The courtesy lamps are controlled by the body control module (BCM). Inputs from the dome lamp switch and the door ajar switches are monitored by the BCM. When a door ajar switch is closed the BCM supplies the ground for the courtesy lamps or the dome lamp switch is turned to the ON position. The BCM also supplies the voltage for the courtesy lamps.

Schematic Reference

Interior Lights Schematics

Electrical Information Reference

Scan Tool Reference

Ignition ON, observe the scan tool Interior Light Command in Vehicle Access while OPENING and CLOSING all of the doors. The courtesy lamps should change between OFF and ON.

Dome Lamp Switch Circuit Testing

1. Ignition OFF, disconnect the harness connector at the dome lamp switch.
2. Ignition OFF, test for less than 1.0 ohm between the ground circuit and ground.

⇒	If greater than 1.0 ohm, test the ground circuit for an open/high resistance.

3. Verify the scan tool door lamp command parameter is OFF.

⇒	If the interior light command is not OFF, test the signal circuit for a short to ground. If the circuit tests normal, replace the BCM.

4. Install a 3-amp fused jumper wire between the voltage supply circuit and ground. Verify the Scan Tool Interior Light Command parameter is ON.

⇒	If the interior light command is not ON, test the signal circuit of the dome lamp switch for a short to voltage or an open/high resistance. If circuit tests normal, replace the BCM.

5. Install a 3-amp fused jumper wire between the voltage supply circuit and door signal circuit. Verify the Scan Tool Interior Light Command parameter is ON when a door is in the open position.

⇒	If the interior light command is not ON, test the signal circuit of the dome lamp switch for a short to voltage or an open/high resistance. If circuit tests normal, replace the BCM.

6. If all circuits test normal, test or replace the dome lamp switch.

Door Jamb Switch Circuit Testing

Important:  This test can be performed on any of the door jamb switches.

1. Ignition OFF, disconnect the harness connector at the inoperative door ajar switch.
2. Ignition OFF, test for less than 1.0 ohm between the ground circuit and ground.

⇒	If greater than 1.0 ohm, test the ground circuit for an open/high resistance.

3. Verify the scan tool interior light command parameter is OFF.

⇒	If the interior light command is not OFF, test the signal circuit for a short to ground. If the circuit tests normal, replace the BCM.

4. Install a 3-amp fused jumper wire between the voltage supply circuit and ground. Verify the scan tool interior light command parameter is ON.

⇒	If the dome lamp is not ON, test the signal circuit of the door jamb switch for a short to voltage or an open/high resistance. If circuit tests normal, replace the BCM.

5. If all circuits test normal, test or replace the door jamb switch.

Dome Lamp Switch Testing

1. Ignition OFF, disconnect the harness connector at the dome lamp switch.
2. Test for infinite resistance between the 2 signal terminals with the switch being in the opposite position and the voltage supply terminal.

⇒	If less than infinite resistance, replace the dome lamp switch.

3. Test for less than 2.0 ohms between each of the signal terminals with the switch in the appropriate position and the voltage supply terminal.

⇒	If greater than 2.1 ohms, replace the dome lamp switch.

Door Jamb Switch Testing

Important: This test can be performed on any of the door jamb switches.

1. Ignition OFF, disconnect the harness connector at the door jamb switch.
2. Test for infinite resistance between the signal terminal and the voltage supply terminal with the switch in the open position.

⇒	If less than infinite resistance, replace the door jamb switch.

3. Test for less than 1.0 ohms between the signal terminal and the voltage supply terminal with the switch in the closed position.

⇒	If greater than 1.0 ohms, replace the door jamb switch.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.