Circuit Description
The body control module (BCM) turns on the park lamp relay when the ambient light sensor senses a dark condition or the headlamp switch is placed in the PARK position. Battery positive voltage is supplied to the relay at all times through the PARK LPS fuse. The BCM grounds the park lamp relay control circuit in order to activate the relay.
Conditions for Running the DTC
| • | The ignition switch is in the ON position. |
| • | The ambient light sensor senses a dark condition (park lamps on). |
Conditions for Setting the DTC
| • | The park lamp relay control circuit is open or shorted to battery voltage for 5 seconds. |
| • | The park lamp relay output circuit is open, shorted to ground or battery voltage for 5 seconds. |
| • | A faulty junction block |
Action Taken When the DTC Sets
| • | The SERVICE indicator will illuminate. |
| • | The check gages chime sounds. |
Conditions for Clearing the DTC
| • | The conditions for setting the DTC are no longer present. |
| • | A history DTC clears after 100 malfunction free ignition cycles. |
| • | The BCM receives the clear code command from the scan tool. |
Diagnostic Aids
If the DTC is a history DTC, the problem may be intermittent. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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Listen for an audible click when the ALC park lamp relay operates. Command both the ON and OFF states. Repeat the commands as necessary.
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Tests for voltage at the coil side of the ALC park lamp relay . The PARK LPS fuse supplies power to the coil side of the ALC park lamp relay.
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Verifies that the body control module is providing ground to the ALC park lamp relay.
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Exterior Lights Schematics | |||
1 | Did you perform the Lighting System Diagnostic System Check? | Go to Step 2 | |
Does the ALC park lamp relay turn ON and OFF with each command? | Go to Step 5 | Go to Step 3 | |
Does the test lamp illuminate? | Go to Step 4 | Go to Step 9 | |
Does the test lamp turn ON and OFF with each command? | Go to Step 7 | Go to Step 6 | |
5 | Test the park lamp supply voltage circuit for an open, high resistance, or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 12 | Go to Step 8 |
6 | Test the control circuit of the ALC park lamp relay for an open, high resistance, or a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 12 | Go to Step 8 |
7 | Inspect for poor connection at the ALC park lamp relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 12 | Go to Step 10 |
8 | Inspect for poor connections at the harness connector of the body control module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 12 | Go to Step 11 |
9 | Repair an open, high resistance, or short to ground in the coil side battery positive voltage circuit of the ALC park lamp relay. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 12 | -- |
10 | Replace the ALC park lamp relay. Did you complete the replacement? | Go to Step 12 | -- |
11 |
Important: Perform the set up procedure for the body control module. Replace the body control module. Refer to Body Control Module Replacement . Did you complete the replacement? | Go to Step 12 | -- |
12 |
Does the DTC reset? | Go to Step 2 | System OK |
