Circuit Description
The body control module (BCM) monitors the park lamp switch on signal circuit and the headlamp switch headlamps on signal circuit in order to determine when the park lamps and headlamps should be illuminated. When the headlamp switch is turned to PARK, the BCM senses that the park lamp switch signal on circuit is grounded and the headlamps switch headlamps ON signal circuit is open. The BCM will then energize the park lamp relay illuminating the park lamps. When the headlamp switch is turned to HEAD, the BCM senses that the park lamp switch on signal circuit and the headlamp switch headlamps ON signal circuit are grounded. The BCM will then energize the park lamp relay and headlamp low beam relay or high beam relay illuminating the park lamps and headlamps.
Conditions for Running the DTC
The battery voltage must be between 9.0-16.0 volts.
Conditions for Setting the DTC
| • | The headlamp switch park lamps ON signal circuit is open or has a high resistance. |
| • | The headlamp switch headlamps ON signal circuit is shorted to ground. |
Action Taken When the DTC Sets
The park lamps will not operate or the headlamps will illuminate without the park lamps.
Conditions for Clearing the MIL/DTC
| • | This DTC will clear on current status after the condition for setting the fault is corrected. |
| • | A history DTC will clear after 100 consecutive ignition cycles without a fault present. |
| • | History and current DTCs can be cleared using a scan tool. |
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Exterior Lights Schematics Connector End View Reference: Lighting Systems Connector End Views or Body Control System Connector End Views in Body Control System | |||
1 | Did you perform the Lighting Systems Diagnostic System Check? | Go to Step 2 | |
2 |
Does the scan tool display park lamps ACTIVE and the headlamps INACTIVE? | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | Go to Step 3 |
3 | Test the park lamp switch ON signal circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct a condition? | Go to Step 10 | Go to Step 4 |
4 | Test the headlamp switch headlamps ON signal circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct a condition? | Go to Step 10 | Go to Step 5 |
5 |
Is continuity present? | Go to Step 6 | Go to Step 7 |
6 | Inspect for poor connections at the harness connector of the BCM. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 10 | Go to Step 8 |
7 | Inspect for poor connections at the harness connector of the headlamp switch. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 10 | Go to Step 9 |
8 |
Important: Perform the setup procedure for the BCM. Replace the BCM. Refer to Body Control Module Replacement in Body Control System. Did you complete the replacement? | Go to Step 10 | -- |
9 | Replace the headlamp switch. Refer to Headlamp Switch Replacement . Did you complete the replacement? | Go to Step 10 | -- |
10 |
Does the DTC reset? | Go to Step 2 | System OK |
