When the headlamp switch is moved to the PARK or ON position, battery voltage is applied through CKT 9 to the left instrument panel fuse block (LIPFB). Battery power passes through the LIPFB to both license lamps, both tail lamps, both front park/turn lamps, both rear tail lamps, and all marker lamps through CKT 9. The front marker and front park/turn lamps are grounded by CKT 150 through the forward lamp ground splice pack.

Automatic Lighting Control (ALC)

The body control module (BCM) monitors circuit 79 to determine if the headlamps (park lamp) switch is active or inactive. The automatic light control (ALC) system will be inactive if the headlamp, park lamp switch is active. The headlamp relay is commanded on by the BCM through circuit 352. The BCM also monitors 352 for feedback when the headlamp relay is commanded. The system uses light sensor circuit 1137 to switch the ALC on after dark.

Daytime Running Lamps

Daytime running lamps are standard on all Saturn models. The DRL relay is located in the UHFB. The coil side of the DRL relay receives battery voltage through the left headlamp fuse. Battery voltage flows through the DRL relay coil to the body control module through CKT 592. The BCM will ground CKT 592 when DRL is required. The BCM uses ignition, park lamp, headlamp, high beam and park brake inputs to control DRL. The DRL will be enabled anytime the ignition is in the RUN position, the headlamp switch is Off and the park brake switch is Off.

Battery voltage is supplied through the left headlamp fuse to CKT 40 to the left high beam lamp. Voltage flows through the left high beam lamp to the IPFB through CKT 1200. Voltage flows to the right DRL relay located in the IPFB through CKT 593. The BCM provides ground to CKT 592 to energize the relay. Voltage flows through the closed contacts of the DRL relay to ground through CKT 150 to the forward lamp ground splice pack. This circuit results in both high beam lamps being connected in series, which allows the high beam lights to operate at half brightness.

The BCM will turn Off the DRL relay when it sees any of the following inputs:

The BCM uses the high beam input to determine if the DRL functions are working. If the DRL functions are not operating properly a diagnostic trouble code may be set. Refer to diagnosis in this section for further information.

Headlamps

Battery power is applied to the low and high beam elements of the left headlamp assembly by the left headlamp fuse through CKT 40. Battery power is applied to the low beam element of the right headlamp assembly by the right headlamp fuse through CKT 140. Battery power is applied to the right high beam element by the right headlamp fuse normally closed (DRL relay NOT energized) contacts of the DRL relay and CKT 593.

When the headlamp switch is turned to ON, and the high beam switch is OFF, a ground path is provided to CKT 1201 through the headlamp switch to CKT 550. CKT 550 is connected to the LIPFB and is grounded at the right body ground splice pack. When the high beam switch is in the ON position, a ground path is provided to CKT 1200 through the headlamp switch to CKT 550. CKT 550 is connected to the LIPFB and is grounded at the right body ground splice pack. This same operation is also true when the flash-to-pass feature is used. To operate the flash-to-pass feature, the multifunction lever is pulled toward the driver.

Stop Lamps

Battery voltage is applied at all times to the brake switch from the brake/park lock fuse through CKT 540. When the brake switch is closed (brake pedal pushed down) battery voltage is applied to the LIPFB through CKT 20. The LIPFB distributes battery voltage to the stop lamps through CKT 20. The stop lamps are grounded by CKT 650 through the rear body ground splice pack. The two stop lamps for the wagon are grounded by CKT 650 through the tail lamp ground.

Turn Signals

When the ignition switch is turned to the RUN position, battery voltage is applied to the hazard switch from the backup/turn fuse through CKT 239. This battery voltage is then applied to the headlamp/turn signal switch through CKT 16.

During a left hand turn, battery voltage is applied to CKT 14, which in turn supplies voltage to the left front park turn lamp through the underhood fuse block, to the left rear turn lamp through the left instrument panel fuse block and the instrument cluster.

During a right hand turn, battery voltage is applied to CKT 15, which in turn supplies voltage to the left instrument panel fuse block (LIPFB). Battery voltage flows through the LIPFB to the right front park turn lamp through the underhood fuse block, to the right rear turn lamp and the instrument cluster.

The front park/turn lamps ground through CKT 150 to the forward lamp splice pack. The rear turn lamps ground through CKT 650 to the rear body splice pack on the sedan, and the tail lamp ground on the wagon.

Fog Lamps

The fog lamp system consists of a fog lamp relay, a fog lamp switch, and the fog lamps. Battery voltage is applied to the fog lamp relay and the fog lamp switch through CKT 9, from the headlamp switch. The fog lamps will only operate when the headlamp switch is in the ON or PARK position. When the headlamp switch is in the ON or PARK position, and the fog lamp switch is pressed, current will flow through the coil side of the fog lamp relay through CKT 317 to the fog lamp switch. Current will also flow through CKT 9 to the fog lamp on indicator. Current flow from the fog lamp switch grounds through CKT 450 to the right body ground splice pack (with RKE) or the right body ground (w/o RKE).

When the fog lamp relay is energized, battery voltage is applied from the 10A FOG LP fuse to CKT 34 to the fog lamps. The fog lamps ground through CKT 150 to the forward lamp ground splice pack.

Hazard Lamps

Battery voltage is always applied from the 10A HAZARD fuse to the hazard switch through CKT 1040. When the hazard switch is pressed, battery voltage is fed through the timing circuitry inside the hazard switch. This pulsating voltage is fed to the right tail lamp and right front park turn lamp through CKT 15, and the left rear tail lamp and left front park/turn lamp through CKT 14. Both front park/turn lamps are grounded through CKT 150 at the forward lamp splice pack, and the tail lamps are grounded through CKT 650 at the rear compartment ground splice pack on the sedan, and the tail lamp ground on the wagon.

Back-Up Lamps

Battery voltage is supplied to the transaxle range switch (automatic) or the back up switch (manual) from the 10A back-up/turn fuse in the UHFB through CKT 239. Current flows through the switch, through CKT 24 to the back up lamps. The lamps are grounded through CKT 650 to the rear compartment ground splice pack (sedan) or tail lamp ground (wagon).