Off-Road Lamps Malfunction

Off-Road Lamps Malfunction

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions) provides an overview of each diagnostic category.



Diagnostic Fault Information






Circuit/System Description

The off-road lamps are dealer installed and can be purchased in different applications with lights mounted on the roof and on the front brush guard. Voltage is supplied to the Off Road Grille Lamp Relay or Off Road Roof Lamp Relay at all times. The appropriate relay is then supplied ground through the Off Road Grille or Roof Lamp Switch, energizing the appropriate relay. Voltage is then applied to the Off Road Grille or Roof Lamps. The lamps are controlled by rocker type switches located on the instrument panel.


Reference Information
Schematic Reference

Exterior Lights Schematics (Exterior Lights Schematics)
Connector End View Reference

Component Connector End Views (Component Connector End Views)
Description and Operation

Exterior Lighting Systems Description and Operation (Exterior Lighting Systems Description and Operation)
Electrical Information Reference

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information


Circuit/System Verification

Ignition ON, turn the roof or grille lamp switch on and verify that both exterior lamps and switch indicator illuminate.


Circuit/System Testing


Off Road Grille Lamps and Roof Lamps Malfunction
1. Ignition OFF, disconnect the appropriate relay.
2. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal 85 and ground.

• If the test lamp illuminates, test the control circuit for a short to voltage.

3. Verify that a test lamp illuminates between the B+ circuit terminal 86 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 B+ circuit fuse is open, test the control circuit terminal 87 for a short to ground. If the circuit tests normal, test or replace the relay.

4. Verify that a test lamp illuminates between the B+ circuit terminal 30 and ground.

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

5. Disconnect the harness connector at the appropriate lamp.
6. Test for less than 1 ohm between the ground circuit terminal B and ground.

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

7. Connect the harness connector at the appropriate lamp.
8. Connect a 20A fused jumper wire between the B+ circuit terminal 30 and the control circuit terminal 87. Verify the test lamp is illuminated.

• If the lamp does not illuminate, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, test or replace the appropriate lamp.

9. Connect a test lamp between the B+ circuit terminal 86 and the control circuit terminal 85.
10. Turn the switch ON and OFF. The test lamp should turn ON and OFF.

• If the test lamp is always ON, test the control circuit terminal 85 for a short to ground. If the circuit tests normal, replace the appropriate switch.


• If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the appropriate switch.

11. If all circuits test normal, test or replace the appropriate relay.



Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Off Road Lamp Switch Replacement (Service and Repair)
* Off Road Lamp Bulb Replacement (Off Road Lamp Bulb Replacement)