Headlamp Switch Input Circuit High

Monitored & Set Condition

When Monitored: With Igniton On.
Set Condition: The BCM detects a voltage greater than 4.75-volts on the Headlamp Switch Input for more than 5 seconds.

Possible Causes:

Intermittent Condition
Headlamp Switch Open
Headlamp Switch MUX Circuit Open
Headlamp Switch Return Circuit Open
Body Control Module

Testing

Turn the ignition on. With the DRBIII(R), erase all BCM DTC's. Turn the headlamps to the ON position. With the DRBIII(R), read DTCs. Does the DRBIII(R) display: HEADLAMP SWITCH INPUT CKT HIGH? If yes, go to next step. If no, the condition that caused the symptom is currently not present. Inspect the related wiring for a possible intermittent condition. Look for any chafed, pierced, pinched, or partially broken wires. Perform BODY VERIFICATION TEST .
Turn the ignition off. Disconnect the Headlamp Switch harness connector. Connect a jumper wire between the Headlamp Switch MUX circuit and the Headlamp Switch Return circuit in the Headlamp Switch harness connector. Turn the ignition on. With the DRBIII(R), select Body, Body Controller and read: Headlamp Switch volts. Does the DRBIII(R) display Headlamp Switch voltage below 0.5volts? If yes, replace the Headlamp Switch. Perform BODY VERIFICATION TEST . If no, go to next step.
Turn the ignition off. Disconnect the Body Control Module harness connector. Measure resistance of the Headlamp Switch MUX circuit from the Body Control Module connector to the Headlamp Switch harness connector. Is the resistance above 5.0 ohms? If yes, repair the Headlamp Switch MUX circuit for an open condition. Perform BODY VERIFICATION TEST . If no, go to next step.
Measure resistance of the Headlamp Switch Return circuit from the Body Control Module connector to the Headlamp Switch harness connector. Is the resistance above 5.0 ohms? If yes, repair the Headlamp Switch Return circuit for an open condition. Perform BODY VERIFICATION TEST . If no, replace the Body Control Module. Perform BODY VERIFICATION TEST .