No Response From AHLM (Automatic Headlamp Leveling Module)

NO RESPONSE FROM AHLM (AUTOMATIC HEADLAMP LEVELING MODULE)





For a complete wiring diagram, refer to the Wiring Information.






NOTE: The Automatic Headlamp Leveling Module (AHLM) is part of the Right Front Lamp Assembly.

1. TEST FOR INTERMITTENT CONDITION

NOTE: Check for any TSB(s) related to the condition. If a TSB applies, perform the procedure outlined in the TSB before continuing.

1. Turn the ignition on.

NOTE: Make sure the IOD fuse is installed and battery voltage is between 10.0 and 16.0 volts.

2. With the scan tool, read the module status.

NOTE: Check the TIPM for any active CAN hardware DTCs, perform DTC before proceeding.

Does the scan tool indicate that the module is active on the bus?

Yes

- The no response condition is not present at this time. Using the wiring diagrams as a guide, check all related splices and connectors for signs of water intrusion, corrosion, pushed out or bent terminals, and correct pin tension.

No

- Go To 2

2. CHECK THE (F921) FUSED RUN RELAY OUTPUT CIRCUIT FOR AN OPEN OR SHORT




1. Turn the ignition off.
2. Disconnect the Right Front Lamp Assembly harness connector.
3. Turn the ignition on.
4. Using a 12-volt test light connected to ground, check the (F921) Fused Run Relay Output circuit.

Does the test light illuminate brightly?

Yes

- Go To 3

No

- Repair the open or short in the (F921) Fused Run Relay Output circuit.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

3. CHECK THE (L910) RIGHT HEADLAMP RETURN SIGNAL CIRCUIT FOR AN OPEN




1. Turn the ignition off.
2. Using a 12-volt test light connected to 12-volts, check the (L910) Right Headlamp Return Signal circuit.

Does the test light illuminate brightly?

Yes

- Go To 4

No

- Repair the open in the (L910) Right Headlamp Return Signal circuit.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

4. CHECK THE (D64) AND (D65) CAN C BUS CIRCUITS FOR AN OPEN




1. Disconnect the TIPM C1 harness connector.
2. Measure the resistance of the (D64) CAN C Bus (-) circuit between the Right Front Lamp Assembly harness connector and the TIPM C1 harness connector.
3. Measure the resistance of the (D65) CAN C Bus (+) circuit between the Right Front Lamp Assembly harness connector and the TIPM C1 harness connector.

Is the resistance below 5.0 Ohms?

Yes

- Replace the Right Front Lamp Unit. Front Lamp Unit - Removal.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

No

- Repair the open or high resistance in the (D65) or (D64) CAN C Bus circuit.
- Perform the BODY VERIFICATION TEST. Body Verification Test.