Sierra 1500 4WD V8-5.3L VIN B (2005)
Tail Lamp: Description and Operation
PARK, TAIL AND MARKER LAMPS
The park, tail and marker lamps, including the license lamps, are turned on when the headlamp switch is placed in the PARK or HEAD position or
anytime the headlights are requested. The underhood fuse block supplies battery positive voltage to both the park lamp relay switch contacts and the park
lamp coil circuit. The body control module (BCM) provides a ground or control circuit to the park lamp relay coil circuit. When the park lamps are
turned on the BCM energizes the park lamp relay. Current flow is from the park lamp relay to the FR PRK 10-ampfuse, RR PRK 10-amp fuse, LR PRK
10-amp fuse, and the TRL PRK 10-ampfuse, and to their respective park and marker lamps. The front park and marker lamps are grounded at G100.
The rear park and marker lamps are grounded at G401. The license lamps are grounded at G410. If the headlight switch is left in the ON position, the
inadvertent power control feature will turn off the park, tail and marker lamps approximately 10 minutes after the ignition switch is turned to the OFF
position. If the driver places the headlight switch in the ON position after the ignition switch has been turned OFF, or if the ignition switch is in the
ACCY position, the park, tail and marker lamps will remain ON until turned OFF or the battery runs dead.
