Battery voltage is supplied at all times to the dome lamps from the CTSY LAMPS Fuse 9 (C4/C5) or Circuit Breaker 9 (C6/C7/C8) located in the I/P 1 fuse block. The dome lamp can be turned ON in 3 different ways; when any door is opened, dome lamp switch, and by the remote control door lock receiver (RCDLR). When a door is opened, ground is applied through the door latch, the dome lamp defeat switch, and the control circuit illuminating the dome lamp until the door is closed. When the dome lamp defeat switch is pressed, the normally closed switch contacts open preventing the activation of dome lamp when opening the doors. The dome lamp then can be turned ON only by using the dome lamp switch or by the RCDLR. Dome lamps with C95 also contains two reading lamps that illuminate only when their switch is placed in the ON position.

Schematic Reference

Interior Lights Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Interior Lighting Systems Description and Operation

Electrical Information Reference

Scan Tool Reference

Control Module References for scan tool information

All doors closed, turn the dome lamps ON and OFF using the dome lamp switch. The dome lamps should turn ON and OFF when changing between commanded states.

Dome Lamps Always ON

1. Ignition OFF, disconnect the harness connector at the components listed below. The dome lamps should turn OFF.

•	Driver Door Latch Assembly X2

•	Passenger Door Latch Assembly X2

•	Left Rear Door Latch Assembly X2 - Crew Cab

•	Right Rear Door Latch Assembly X2 - Crew Cab

•	Remote Control Door Lock Receiver (RCDLR) +AUO

•	Headlamp Switch

⇒	If the dome lamp is still illuminated, test the dome lamp control circuit for a short to ground.

2. Connect each component one at a time and verify the dome lamp does not turn ON.

⇒	If the dome lamps turn ON, test or replace the component responsible for turning ON the dome lamp.

Dome Lamps Inoperative +AUO

1. Ignition OFF, disconnect the harness connector at the headlamp switch.
2. Test for less than 1.0 ohm between the ground circuit terminal R and ground.

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

3. Connect the harness connector at the headlamp switch and disconnect the harness connector at the inoperative dome lamp.
4. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal A and ground.

⇒	If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.

5. Install a test lamp between the control circuit terminal B and B+.
6. Command the dome lamp ON using the dome lamp switch. The test lamp should illuminate.

⇒	If the test lamp does not illuminate, test the control circuit for an open/high resistance. If the circuit tests normal, test or replace the headlamp switch.

7. Ignition OFF, connect the harness connector at the dome lamp and disconnect the harness connector at the headlamp switch.
8. Open the appropriate door, test for less than 5 ohms between the control circuit terminal L and ground.

⇒	If greater than the specified range, test the control circuit for an open/high resistance. If the circuit tests normal, test or replace the door latch assembly.

9. Connect the harness connector at the headlamp switch and disconnect the harness connector at the RCDLR.
10. Open the appropriate door, test for less than 5 ohms between the control circuit terminal K and ground.

⇒	If greater than the specified range, test or replace the headlamp switch.

11. Install a 10A fused jumper wire between the control circuit terminal S and ground. The dome lamp should illuminate.

⇒	If the dome lamp does not illuminate, test the control circuit for an open/high resistance. If the circuit tests normal, test or replace the dome lamp bulb.

12. If all circuits test normal, replace the RCDLR.

Dome Lamps Inoperative -AUO

1. Ignition OFF, disconnect the harness connector at the headlamp switch.
2. Test for less than 1.0 ohm between the ground circuit terminal R and ground.

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

3. Connect the harness connector at the headlamp switch and disconnect the harness connector at the inoperative dome lamp.
4. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal A and ground.

⇒	If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.

5. Install a test lamp between the control circuit terminal B and B+.
6. Command the dome lamps ON using the dome lamp switch. The test lamp should illuminate.

⇒	If the test lamp does not illuminate, test the control circuit for an open/high resistance. If the circuit tests normal, test or replace the headlamp switch.

7. Ignition OFF, connect the harness connector at the dome lamp and disconnect the harness connector at the headlamp switch.
8. Open the appropriate door, test for less than 5 ohms between the control circuit terminal L and ground.

⇒	If greater than the specified range, test the control circuit for an open/high resistance. If the circuit tests normal, test or replace the door latch assembly.

9. Install a 10A fused jumper wire between the control circuit terminal B and ground. The dome lamp should illuminate.

⇒	If the dome lamp does not illuminate, test the control circuit for an open/high resistance. If the circuit tests normal, replace the dome lamp bulb.

10. If all circuits test normal, test or replace the headlamp switch.

Driver and Rear Passenger Door Latch

1. Ignition OFF, disconnect the harness connector at the appropriate door latch.
2. Test for infinite resistance between control terminal A and ground terminal D with the latch in Inactive position.

⇒	If less than the specified range, replace the door latch.

3. Test for less than 1.0 ohm between the control terminal A and the ground terminal D with the latch in Active position.

⇒	If greater than the specified range, replace the door latch.

Front Passenger Door Latch

1. Ignition OFF, disconnect the harness connector at the front passenger door latch.
2. Test for infinite resistance between control terminal D and ground terminal A with the latch in Inactive position.

⇒	If less than the specified range, replace the door latch.

3. Test for less than 1.0 ohm between the control terminal D and the ground terminal A with the latch in Active position.

⇒	If greater than the specified range, replace the door latch.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.