B2587

CIRCUIT DESCRIPTION
The body control module (BCM) turns on the auto parklamp control relay when the ambient light sensor senses a dark condition. Battery positive voltage is supplied to the auto parklamp control relay at all times through the PARK LPS fuse. The BCM grounds the auto parklamp control 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 light condition (ALC parklamps off).

CONDITIONS FOR SETTING THE DTC
^ The auto parklamp control relay control circuit is shorted to ground or open for 5 seconds.
^ 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.
^ The check gauges 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 and Poor Connections in Diagrams.

TEST DESCRIPTION

Steps 1-6:

Steps 7-13:

The number(s) below refer to the step number(s) on the diagnostic table.
2. Listen for an audible click when the auto parklamp control relay operates. Command both the ON and OFF states. Repeat the commands as necessary.
3. Tests for voltage at the coil side of the auto parklamp control relay. The PARK LPS fuse supplies battery positive voltage to the coil side of the auto parklamp control relay.