For 1990-2009 cars

Battery voltage is applied to the headlamp bulbs at all times. The headlamps are controlled by supplying the ground for the lamps through the turn/headlamp switch assembly or the body control module (BCM). When the turn/headlamp switch is in the ON position, the ground is supplied through CKT 150.

The BCM controls the daytime running lamps (DRL). The system allows the headlamps to operate at a reduced intensity under the following conditions:

• | The engine is running.

• | The transaxle is not in the PARK position.

• | The normal headlamps are turned OFF.

The BCM activates the system by grounding CKT 592. This action energizes the DRL relay. This condition allows a reduced voltage to flow to the headlamps. When the headlamp switch is turned to ON, the headlamps operate normally.

The parking brake provides an input to the BCM. When the parking brake is engaged, the DRL remain disabled until the parking brake is disengaged.

The fog lamp switch provides an input to the BCM. The BCM opens the fog lamp relay under the following conditions:

• | The BCM receives an ON signal from the fog lamp switch.

• | The ignition switch is in the RUN position.

• | The headlamp switch is the PARK or HEAD position.

When the headlamp switch is in the HEAD position, ensure that the high/low beam switch is the LOW position in order for the BCM to enable the fog lamp relay.

The BCM controls the headlamps and the parking lamps by energizing the automatic lamp control relay. The BCM uses an ambient light sensor for the following purposes:

• | In order to determine available light levels

• | In order to determine when to energize the automatic lamp control relay

The BCM energizes the parking lamp relay in order to turn the exterior lamps on.