Headlamp Leveling Malfunction TR6

Each headlamp assembly contains a headlamp leveling motor that is controlled by the headlight switch. The headlight switch is a resistance ladder switch and wired to each headlamp leveling motor. With the ignition in ON position the headlight switch and each headlamp leveling motor is applied to B+. Each headlamp leveling motor is permanently grounded.

Schematic Reference

Headlight Leveling Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Exterior Lighting Systems Description and Operation

Electrical Information Reference

Scan Tool Reference

Control Module References for scan tool information

Ignition ON, cycle the headlamp leveling switch in each position while observing both headlamps. Both headlamps should operate to the appropriate position when commanded.

1. Ignition OFF, disconnect the harness connector at the appropriate headlamp assembly.
2. Ignition OFF, test for less than 5 Ω between the ground circuit terminal 7 and ground.

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

3. Ignition ON, connect a test lamp between the ignition circuit terminal 6 and ground. The test lamp should illuminate.

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

4. Ignition OFF, disconnect the harness connector at the S30 Headlamp Switch.
5. Ignition ON, connect a test lamp between the ignition circuit terminal 9 and ground. The test lamp should illuminate.

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

6. Ignition ON, test for less than 0.3 V between the signal circuit terminal 10 and ground.

⇒	If greater than the specified range, test the signal circuit for a short to voltage.

7. Ignition OFF, test for greater than 500 kΩ between the signal circuit terminal 10 and ground.

⇒	If less than the specified range, test the signal circuit for a short to ground.

8. Ignition OFF, test for less than 5 Ω between the signal circuit terminal 10 at the S30 Headlamp Switch and the control circuit terminal 8 at the appropriate headlamp assembly.

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

9. Ignition OFF, reconnect the harness connector at the S30 Headlamp Switch. Connect a test lamp between the control circuit terminal 8 at the appropriate headlamp assembly and ground.
10. Switch the headlamp leveling switch in each position. The test lamp illumination should change in each position.

⇒	If the test lamp does not illuminate or does not change their illumination, replace the S30 Headlamp Switch.

11. If all circuits test normal, replace the appropriate headlamp assembly.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Headlamp Leveling Malfunction TT6 TT2

Battery positive voltage is applied to the headlamp control module at all times. The headlamp control module has a normal operational voltage range of about 12.5-16 V and is only fully functional with the ignition switch is in the RUN position and the headlamp switch in the AUTOMATIC LIGHT position. The communications enable signal from the body control module (BCM) wakes the headlamp control module microprocessor. The headlamp control module receives serial data messages from the engine control module (ECM), transmission control module (TCM), electronic brake control module (EBCM), and BCM with information regarding power mode, speed, steering angle, transmission gear selection, and headlamp switch status. The headlamp control module calculates the headlamp angle and sends commands to the left and right adaptive forward lighting system headlamp actuators. The headlamp actuators drive the headlamps to the position commanded by the headlamp control module. The headlamp control module monitors the headlamp actuator motor control circuits for proper circuit continuity and for shorts to ground or voltage. If a malfunction is detected, a DTC will be stored in memory and the driver will be notified with a message displayed over the driver information center located on the instrument cluster.

Schematic Reference

Headlight Leveling Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Exterior Lighting Systems Description and Operation

Electrical Information Reference

Scan Tool Reference

Control Module References for scan tool information

1. Ignition OFF, disconnect the harness connector at the appropriate headlamp assembly.
2. Ignition OFF, test for less than 5 Ω between the ground circuit terminal 8 and ground.

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

3. Ignition ON, headlamps ON, connect a test lamp between the ignition circuit terminal 6 and ground. The test lamp should illuminate.

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

4. If all circuits test normal, replace the appropriate headlamp assembly. Verify that the customer concern is not still present.

⇒	If the customer concern is still present, replace the K26 Headlamp Control Module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.