Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Headlamp Leveling Motor B+ -- Left | 1 | 1 | -- | -- |
Headlamp Leveling Motor B+ -- Right | 1 | 1 | -- | -- |
Headlamp Leveling Motor Switch Signal | 2 | 2 | 2 | -- |
Headlamp Leveling Motor Control | 1 | 1 | 1 | -- |
Headlamp Leveling Motor Ground -- Left | -- | 1 | -- | -- |
Headlamp Leveling Motor Ground -- Right | -- | 1 | -- | -- |
Headlamp Leveling Switch Ground | 2 | 2 | -- | -- |
1. Headlamp Leveling Malfunction 2. Headlamp Leveling Switch Malfunction | ||||
Circuit/System Description
The HD LMP LEVELING fuse in the underhood fuse block supplies B+ to the headlamp leveling switch and headlamp leveling motors. When the driver places the headlamp leveling switch in any position, a signal is sent to the headlamp leveling motors to adjust the headlight aiming to one of three positions. Ground for the headlamp leveling switch is provided by the BCM and ground is supplied to the headlamp leveling motors at G105. When position III is selected on the headlamp leveling switch, the headlamps will automatically be illuminated.
Reference Information
Schematic Reference
Connector End View Reference
Description and Operation
Exterior Lighting Systems Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
Ignition ON, adjust the headlamp leveling switch from the highest to lowest setting and verify that both headlamp leveling actuators operate.
| ⇒ | If one leveling actuator is inoperative, refer to the Headlamp Leveling Actuator Malfunction. |
| ⇒ | If both leveling actuators are inoperative, refer to the Headlamp Leveling Switch Malfunction. |
Circuit/System Testing
Headlamp Leveling Actuator Malfunction
- Ignition OFF, disconnect the harness connector at the appropriate actuator.
- Test for less than 5.0 ohms between the ground circuit terminal C and ground.
- Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal A and ground.
- Ignition ON, test for 2.0 - 8.0 volts between the switch signal circuit terminal B and ground while operating the leveling switch from the lowest to highest setting.
- If all circuits test normal, test or replace the appropriate actuator.
| ⇒ | If greater than the specified range, test the circuit for an open/high resistance. |
| ⇒ | If the test lamp does not illuminate, test the circuit for a short to ground or an open/high resistance. |
| ⇒ | If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. |
| ⇒ | If greater than the specified range, test the signal circuit for a short to voltage. |
Headlamp Leveling Switch Malfunction
- Ignition OFF, disconnect the harness connector at the headlamp switch.
- Test for less than 5.0 ohms between the low reference circuit terminal 3 and ground.
- Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal 9 and ground.
- If all circuits test normal, test or replace the headlamp switch.
| ⇒ | If greater than the specified range, test the circuit for an open/high resistance. |
| ⇒ | If the test lamp does not illuminate, test the circuit for a short to ground or an open/high resistance. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
