Circuit/System Description
WARNING: This page is about a different car, the 2009 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.
Battery voltage is applied at all times to both the coil and switch sides of the PARK LAMP relay located in the underhood fuse block. The headlamp switch is suppled with ground at G201 at all times. When the headlamp switch is placed in either the HEAD or PARK position, ground is applied to the park lamp signal circuit to the body control module (BCM). The BCM responds by applying ground to the park lamp relay control circuit. This energizes the park lamp relay coil causing the relay switch contacts to close allowing battery voltage to flow through the T/LAMP LT and T/LAMP RT fuses to all of the park, tail, license, and marker lamps.