The exterior lighting system consist of the following lamps:

The headlamps are operated when the driver places the headlamp switch in the HEADLAMP position. The LT HDLP and RT HDLP fuse in the IP fuse block, supply battery positive voltage to both the left and right headlamps. The low beam and high beam circuits continue to the headlamp switch. Depending on the position of the dimmer switch, either the low or high beam circuit will now have a path to ground. Ground is provided at G204. The low beam and high beam circuits also provide the body control module (BCM) with both low and high beam inputs. The headlamp switch includes the dimmer and the flash-to-pass switch.

If the headlight switch is left in the HEADLAMP position, the headlights will remain on until turned off or the battery runs dead.

Any function that turns on the headlights will cancel the daytime running lamps operation. The LT HDLP fuse in the IP fuse block supplies battery positive voltage to the daytime running lamp (DRL) relay coil circuit. The DRL relay switch contacts are connected to the low beam circuit. When the headlamp switch is placed in the OFF position, the BCM will turn on the daytime running lamps. The BCM energizes the DRL relay, closing the switch contacts and grounding the low beam circuit at G204. The DRL illuminate the low beam headlights at a reduced intensity. The DRL will operate when the ignition switch is in the RUN position, the gear selector is not in the PARK position and the parking brake is released. When these conditions have been met the DRL will illuminate.

DRL operation in Manual Transmission equipped vehicles will occur when the ignition switch is in the RUN position, and the parking brake is released.

For Chevrolet, with the park lamps or low beam headlights ON, the fog lights will illuminate when the driver presses the fog lamp switch. The FOG LP fuse in the IP fuse block supplies battery positive voltage to the fog lamp relay switch circuit. The headlamp switch supplies battery positive voltage to the fog lamp relay coil circuit. When the driver presses the fog lamp switch, the body control module (BCM) fog lamp switch input is grounded. The BCM will then energize the fog lamp relay control circuit by providing ground to the fog lamp relay coil. The current flow is now from the fog lamp relay to both front fog lamps and to ground at G102. The state of the fog lamps, either ON or OFF, will remain the same until the fog lamp switch is pressed again. Fog lamp operation will be cancelled whenever the park lamps, are turned OFF or the high beam headlights have been selected.

For Pontiac, with the park lamps or low beam headlights ON, the fog lights will illuminate when the driver presses the fog lamp switch. The FOG LP fuse in the IP fuse block supplies battery positive voltage to the fog lamp relay switch circuit and the fog lamp relay coil circuit. When the driver presses the fog lamp switch, the body control module (BCM) fog lamp switch input is grounded. The BCM will then energize the fog lamp relay control circuit by providing ground to the fog lamp relay coil. The current flow is now from the fog lamp relay to both front fog lamps and to ground at G102. The state of the fog lamps, either ON or OFF, will remain the same until the fog lamp switch is pressed again. Fog lamp operation will be cancelled whenever the park lamps, are turned OFF or the high beam headlights have been selected.

The park, tail and marker lamps, including the license lamps, are turned ON when the headlamp switch is placed in the PARK or HEADLAMP position. The EXT LAMP fuse in the IP fuse block supplies battery positive voltage to the headlamp switch. When the headlamp switch is placed in the PARK or HEADLAMP position, current flows through the headlamp switch to the park, tail and marker lamps and then to ground at G102, G302, and G304. If the park lamps are turned ON , they will remain ON until turned OFF or the battery runs dead.

When the body control module (BCM) receives a door unlock command from the remote keyless entry (RKE) transmitter, the BCM will then flash the headlamps twice. With all the doors closed, and the RKE transmitter is used to lock the doors, the head lamps will flash once. The headlamps will not flash if the rear compartment is opened using the RKE transmitter.

The TURN-B/U fuse and the STOP/HAZ fuse in the IP fuse block, supplies battery positive voltage to the flasher module. The turn signal lamps may only be activated with the ignition switch in the ON position. When the turn signal switch is placed in either the left or right position, current flow is from the flasher module's output to the turn signal switch assembly. The flasher module then sends an on-off voltage signal to either the left or right turn signals and their instrument panel cluster (IPC) indicator. When the hazard switch is pressed, all the turn signal lamps will flash including both IPC turn signal indicators.

The STOP/HAZ fuse in the IP fuse block supplies battery positive voltage to the normally open stop lamp switch. When the driver presses the brake pedal, the switch contacts close and battery positive voltage is supplied to both left and right stop lamp assemblies and the center high mounted stop lamp (CHMSL). The stop lamps are grounded at G302 and G304.

Vehicles equipped with an automatic transmission, the TRN-B/U fuse in the IP fuse block supplies battery positive voltage to the park/neutral position switch. Vehicles equipped with a manual transmission, the TRN-B/U fuse in the IP fuse block supplies battery positive voltage to the back up lamps switch. When the driver places the gear selector lever in the REVERSE position, the current flow is from the park/neutral position switch or the back up lamps switch, to the back up lamps. The back up lamps are grounded at G304.