Circuit/System Testing
Headlamp Leveling Actuator Malfunction
- Ignition OFF, exterior lamps OFF, disconnect the harness connector at the appropriate E13 Headlamp Assembly.
- Test for less than 15 Ω between the ground circuit terminal 9 and ground.
- If 15 Ω or greater
- Ignition OFF.
- Test for less than 2 Ω in the ground circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, repair the open/high resistance in the ground connection.
- Go to next step: If less than 15 Ω
- Ignition ON.
- Verify a test lamp illuminates between the B+ circuit terminal 10 and ground.
- If the test lamp does not illuminate
- Ignition OFF, disconnect the X4 harness connector at the X50A Fuse Block - Underhood.
- Test for infinite resistance between the B+ circuit and ground.
- If less than infinite resistance, repair the short to ground on the circuit.
- Go to next step: If infinite resistance
- Test for less than 2 Ω in the control circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the X50A Fuse Block - Underhood.
- Go to next step: If the test lamp illuminates
- Test or replace the K26 Headlamp Control Module.
- Ignition ON.
- Verify the appropriate headlamp operates to the UP and DOWN positions when commanding the appropriate Headlamp Vertical Motor UP and DOWN with a scan tool.
- If the headlamp does not operate UP and DOWN
Test or replace the E13 Headlamp Assembly.
- Go to next step: If the headlamp operates UP and DOWN
- If the headlamp does not operate UP and DOWN
- All OK.
Headlamp Leveling Sensor Malfunction
- Ignition OFF, disconnect the harness connector at the appropriate B152 Suspension Position Sensor, ignition ON.
- Verify a test lamp illuminates between the low reference circuit terminal 2 and B+.
- If the test lamp does not illuminate
- Ignition OFF, disconnect the harness connector at the K26 Headlamp Control Module.
- Test for less than 2 Ω in the low reference circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the K26 Headlamp Control Module.
- Go to next step: If the test lamp illuminates
- Ignition ON.
- Test for 4.8 - 5.2 V between the 5 V reference circuit terminal 1 and ground.
- If less than 4.8 V
- Ignition OFF, disconnect the harness connector at the K26 Headlamp Control Module.
- Test for infinite resistance between the 5 V reference circuit and ground.
- If less than infinite resistance, repair the short to ground on the circuit.
- Go to next step: If infinite resistance
- Test for less than 2 Ω in the 5 V reference circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the K26 Headlamp Control Module.
- If greater than 5.2 V
- Ignition OFF, disconnect the harness connector at the K26 Headlamp Control Module, ignition ON.
- Test for less than 1 V between the 5 V reference circuit and ground.
- If 1 V or greater, repair the short to voltage on the circuit.
- If less than 1 V, replace the K26 Headlamp Control Module.
- Go to next step: If between 4.8 - 5.2 V
- Verify the appropriate scan tool Leveling Position Sensor Signal parameter is less than 5%.
- If 5% or greater
- Ignition OFF, disconnect the harness connector at the K26 Headlamp Control Module, ignition ON.
- Test for less than 1 V between the signal circuit terminal 3 and ground.
- If 1 V or greater, repair the short to voltage on the circuit.
- If less than 1 V, replace the K26 Headlamp Control Module.
- Go to next step: If less than 5%
- Install a 3 A fused jumper wire between the 5 V reference circuit terminal 1 and the signal circuit terminal 3.
- Engine RUNNING, verify the appropriate scan tool Leveling Position Sensor Signal parameter is greater than 90%.
- If less than 90%
- Ignition OFF, disconnect the harness connector at the K26 Headlamp Control Module.
- Test for infinite resistance between the signal circuit and ground.
- If less than infinite resistance, repair the short to ground on the circuit.
- Go to next step: If infinite resistance
- Test for less than 2 Ω in the signal circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the K26 Headlamp Control Module.
- Go to next step: If 90% or greater
- Test or replace the appropriate B152 Suspension Position Sensor.