Circuit/System Testing

Courtesy Lamp Defeat Switch Malfunction

1. Ignition OFF, disconnect the harness connector at the front dome lamp.
2. Ignition OFF, scan tool OFF, doors CLOSED, interior lamps OFF, test for less than 5 Ω between the ground circuit terminal 4 and ground.
   • If greater than the specified range, test the ground circuit for an open/high resistance.
3. Ignition ON, all doors CLOSED, verify the scan tool Ctsy. Lamp Actv. Reason parameter is Off.
   • If not the specified value, test the signal circuit terminal 2 for a short to ground. If the circuit tests normal, replace the BCM.
4. Install a 3 A fused jumper wire between the signal circuit terminal 2 and ground. Verify the scan tool Ctsy. Lamp Actv. Reason parameter is Manual Defeat.
   • 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, replace the courtesy lamp defeat switch.

Courtesy Lamps Malfunction

1. Ignition OFF, disconnect the harness connector at the inoperative courtesy lamp.
2. Ignition OFF, scan tool OFF, doors CLOSED, interior lamps OFF, test for less than 5 Ω between the appropriate ground circuit terminal listed below and ground.
   • Courtesy lamp - left front door terminal 2
   • Courtesy lamp - right front door terminal 2
   • Courtesy/reading lamp 2nd row terminal B - with UUC
   • Courtesy/reading lamp 2nd row terminal 2 - without UUC
   • Front dome lamp terminal 4
   • Ignition key lamp terminal F
   • I/P compartment lamp terminal 1
   • Rear compartment courtesy lamp - left terminal 1
   • Rear compartment courtesy lamp - right terminal 1
   • Sunshade - left terminal B
   • Sunshade - right terminal B
   • If greater than the specified range, test the appropriate ground circuit for an open/high resistance.
3. Connect a test lamp between the appropriate control circuit terminal listed below and ground.
   • Courtesy lamp - left front door terminal 1
   • Courtesy lamp - right front door terminal 1
   • Courtesy/reading lamp 2nd row terminal C - with UUC
   • Courtesy/reading lamp 2nd row terminal 3 - without UUC
   • Front dome lamp terminal 3
   • Ignition key lamp terminal E
   • I/P compartment lamp terminal 2
   • Rear compartment courtesy lamp - left terminal 2
   • Rear compartment courtesy lamp - right terminal 2
   • Sunshade - left terminal A
   • Sunshade - right terminal A
4. Command the Courtesy Lamps 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.
5. If all circuits test normal, replace the inoperative courtesy lamp.

Reading Lamps Malfunction

1. Ignition OFF, disconnect the harness connector at the inoperative courtesy/reading lamp assembly.
2. Ignition OFF, scan tool OFF, doors CLOSED, interior lamps OFF, test for less than 5 Ω between the appropriate ground circuit terminal listed below and ground.
   • Courtesy/reading lamp 2nd row terminal B - with UUC
   • Courtesy/reading lamp 2nd row terminal 2 - without UUC
   • Front dome lamp terminal 4
   • 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 appropriate control circuit terminal listed below and ground.
   • Courtesy/reading lamp 2nd row terminal A - with UUC
   • Courtesy/reading lamp 2nd row terminal 4 - without UUC
   • Front dome lamp terminal 3
   • If the test lamp does not illuminate, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
4. Remove the BCM VB2 fuse and verify the test lamp turns OFF.
   • If the test lamp remains illuminated, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM.
5. If all circuits test normal, replace the inoperative courtesy/reading lamp assembly.

Underseat lamp Malfunction

1. Ignition OFF, disconnect the harness connector at the inoperative underseat lamp.
2. Ignition OFF, test for less than 5 Ω between the ground circuit terminal D and ground.
   • If greater than the specified range, test the ground circuit for an open/high resistance.
3. Ignition ON, park lamps ON, verify that a test lamp illuminates between the control circuit terminal B and ground.
   • If the test lamp does not illuminate, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the headlamp switch.
4. Verify that a test lamp illuminates between the control circuit terminal C and ground.
   • If the test lamp does not illuminate, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the headlamp.
5. Ignition ON, park lamps OFF, verify that a test lamp does not illuminate between the control circuit terminal B and ground.
   • If the test lamp illuminates, test the control circuit for a short to voltage. If the circuit tests normal, replace the headlamp switch.
6. Verify that a test lamp does not illuminate between the control circuit terminal C and ground.
   • If the test lamp illuminates, test the control circuit for a short to voltage. If the circuit tests normal, replace the headlamp switch.
7. If all circuits test normal, replace the inoperative underseat lamp.