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Home >> Chevrolet >> 2011 >> Camaro LS, Automatic >> Repair and Diagnosis >> External Pages >> Different car >> Section 138 (Lighting System) >> Diagnostic Information and Procedures >> Headlamp Leveling Malfunction >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2012 Chevrolet Camaro. However, it is still accessible from the selected car via links, so may be relevant.

Headlamp Leveling Actuator Malfunction

  1. Ignition OFF, exterior lamps OFF, disconnect the harness connector at the appropriate M29 headlamp leveling actuator. It may take up to 2 minutes for all vehicle systems to power down.
  2. Remove the F39UA 5 A fuse from the X50A fuse block - underhood.
  3. Test for 10 Ω -25k Ω between each control circuit terminal listed below and ground.
    • M29 headlamp leveling actuator control terminal 1
    • M29 headlamp leveling actuator control terminal 2
    • M29 headlamp leveling actuator control terminal 3
    • M29 headlamp leveling actuator control terminal 4
    • If less than 10 Ω 
    1. Ignition OFF, disconnect the harness connector at the K28 headlamp leveling control module.
    2. Test for infinite resistance between the appropriate control circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance, replace the K28 headlamp leveling control module.
    • If greater than 25k Ω 
    1. Ignition OFF, disconnect the harness connector at the K28 headlamp leveling control module.
    2. Test for less than 2 Ω in the appropriate control circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω
    3. Ignition ON.
    4. Test for less than 1 V between the appropriate control circuit and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V, replace the K28 headlamp leveling control module.
    • If between 10 Ω -25k Ω 
  4. Ignition OFF, install the F39UA 5 A fuse at the X50A fuse block - underhood, ignition ON, headlamps ON.
  5. Verify a test lamp does not illuminate between each control circuit terminal listed below and ground.
    • M29 headlamp leveling actuator control terminal 1
    • M29 headlamp leveling actuator control terminal 2
    • M29 headlamp leveling actuator control terminal 3
    • M29 headlamp leveling actuator control terminal 4
    • If the test lamp illuminates 
    1. Ignition OFF, disconnect the harness connector at the K28 headlamp leveling control module, ignition ON.
    2. Test for less than 1 V between the appropriate control circuit and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V, replace the K28 headlamp leveling control module.
    • If the test lamp does not illuminate 
  6. Test or replace the appropriate M29 headlamp leveling actuator.

Headlamp Leveling Sensor Malfunction

  1. Ignition OFF, exterior lamps OFF, disconnect the harness connector at the appropriate B152 suspension position sensor. It may take up to 2 minutes for all vehicle systems to power down.
  2. Test for less than 10 Ω between the low reference circuit terminal 3 and ground.
    • If 10 Ω or greater 
    1. Ignition OFF, disconnect the harness connector at the K28 headlamp leveling control module.
    2. 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 K28 headlamp leveling control module.
    • If less than 10 Ω 
  3. Ignition ON.
  4. Test for 4.8-5.2 V between the 5 V reference circuit terminal 1 and ground.
    • If less than 4.8 V 
    1. Ignition OFF, disconnect the harness connector at the K28 headlamp leveling control module.
    2. 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.
      • If infinite resistance
    3. 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 K28 headlamp leveling control module.
    • If greater than 5.2 V 
    1. Ignition OFF, disconnect the harness connector at the K28 headlamp leveling control module, ignition ON.
    2. 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 K28 headlamp leveling control module.
    • If between 4.8-5.2 V 
  5. Verify the appropriate scan tool Leveling Position Sensor Signal parameter is less than 0.5 V.
    • If 0.5 V or greater 
    1. Ignition OFF, disconnect the harness connector at the K28 headlamp leveling control module, ignition ON.
    2. Test for less than 1 V between the signal circuit terminal 2 and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V, replace the K28 headlamp leveling control module.
    • If less than 0.5 V 
  6. Install a 3 A fused jumper wire between the 5 V reference circuit terminal 1 and the signal circuit terminal 2.
  7. Verify the appropriate scan tool Leveling Position Sensor Signal parameter is greater than 4.8 V.
    • If less than 4.8 V 
    1. Ignition OFF, disconnect the harness connector at the K28 headlamp leveling control module.
    2. Test for infinite resistance between the signal circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance
    3. 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 K28 headlamp leveling control module.
    • If 4.8 V or greater 
  8. Test or replace the appropriate B152 suspension position sensor.
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