Circuit Description
The body control module (BCM) turns ON the park lamp relay when the ambient light sensor senses a dark condition. Battery positive voltage is supplied to the park lamp relay at all times through the PARK LAMP fuse. The BCM grounds the park lamp relay control circuit in order to activate the relay.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC B2587 Park Lamp Relay Output Circuit Low
Conditions for Running the DTC
| • | The ignition switch is in the ON position. |
| • | The ambient light sensor senses a light condition, automatic lamp control (ALC) park lamps OFF. |
Conditions for Setting the DTC
| • | The park lamp relay control circuit is shorted to ground or open for 5 seconds. |
| • | The ALC is not in operation. |
| • | The headlamp switch is not in the PARK position. |
Action Taken When the DTC Sets
The SERVICE indicator will illuminate.
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 .
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 park lamp relay operates. Command both the ON and OFF states. Repeat the commands, as necessary.
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This step tests for voltage at the coil side of the park lamp relay . The PARK LAMP fuse supplies battery positive voltage to the coil side of the park lamp relay.
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Exterior Lights Schematics | |||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | |
Does the park lamp relay turn ON and OFF with each command? | Go to Testing for Intermittent Conditions and Poor Connections | Go to Step 3 | |
Does the test lamp illuminate? | Go to Step 4 | Go to Step 10 | |
4 |
Does the test lamp turn ON and OFF? | Go to Step 8 | Go to Step 5 |
5 | Is the test lamp illuminated? | Go to Step 6 | Go to Step 7 |
6 | Test for a short to ground in the control circuit of the park lamp relay. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 13 | Go to Step 9 |
7 | Test for an open or high resistance in the control circuit of the park lamp relay. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 13 | Go to Step 9 |
8 | Inspect for poor connections at the park lamp relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Step 13 | Go to Step 11 |
9 | Inspect for poor connections at the harness connector of the body control module (BCM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Step 13 | Go to Step 12 |
10 | Repair an open, high resistance, or short to ground in the coil side battery positive voltage circuit of the park lamp relay. Refer to Circuit Testing and Wiring Repairs . Did you complete the repair? | Go to Step 13 | -- |
11 | Replace the park lamp relay. Refer to Relay Replacement . Did you complete the replacement? | Go to Step 13 | -- |
12 | Replace the BCM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | Go to Step 13 | -- |
13 |
Does the DTC reset? | Go to Step 2 | System OK |
