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:

^ Headlamps On
^ Parking brake On
^ Ignition not in the RUN position
^ When automatic lighting control is On and its dark outside.

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 for further information.