The exterior lighting consists of the following lamps:

The headlamps may be turned ON 2 different ways. First, when the headlamp switch is placed in the headlamps position, for normal operation. Second, with the headlamp switch placed in the AUTO position, for automatic lamp control (ALC). During ALC, the headlamps will be in daytime running lamp (DRL) operation in daylight conditions, or headlamp operation in low light conditions.

For headlamp operation, battery positive voltage is applied at all times to the coil and switch sides of the low or high beam relay in the underhood fuse block depending on the position of the headlamp dimmer switch. Ground to the headlamp switch is from G200. When the headlamp switch is placed in the HEAD position, ground is applied to the headlamp switch headlamps ON signal circuit of the body control module (BCM). When either the headlamp switch is placed in the headlamps position or ALC is enabled, the BCM applies a ground to the headlamp low or high beam relay control circuit. This energizes the relay and applies battery positive voltage to the left and right low or high beam fuses in the underhood fuse block, then through the headlamp supply voltage circuits to the headlamps. Ground is applied at all times to the left headlamp from G101 and to the right headlamp from G100.

For high beam operation, the dimmer switch supplies a ground signal to the BCM. Ground to the headlamp dimmer switch is from G200.

For flash-to-pass (FTP) operation, when the headlamp dimmer switch is placed in the FTP position, ground is applied from G200 through the headlamp dimmer switch to the FTP switch signal circuit to the BCM. The BCM then turns the high beam headlamps ON as long as the headlamp dimmer switch is held in the FTP position.

If the headlight switch is left in the headlamps position, the inadvertent power control feature will turn OFF the headlights 10 minutes after the ignition switch is turned to the OFF position. If the driver places the headlight switch in the headlamps position after the ignition switch has been turned OFF, or if the ignition switch is in the ACCY position, the headlights will remain ON until turned OFF or the battery runs dead.

The normal headlamp switch operating position is AUTO, which enables the automatic lamp control (ALC). For ALC operation, the body control module (BCM) receives a signal from the ambient light sensor indicating a low or high ambient (outside) light level. The ambient light sensor is a light sensitive transistor that varies its voltage signal to the BCM in response to changes to the ambient light level. The BCM uses multiple inputs to determine daytime running lamp (DRL) or headlamp low/high beam operation. When the ignition key is turned to the RUN position the BCM determines the light/dark ambient light condition and activates the headlamps or DRL mode immediately. When a transition to the light/dark ambient light condition occurs after the ignition is in the RUN position there is an approximate 30-second delay in the headlamp/DRL transition.

The ALC System also has a defeat feature and a wiper activated headlamps feature. To operate the ALC defeat, turn the headlamp switch counter clockwise one position past the AUTO position after starting the vehicle. This is a momentary switch position, and will return to the AUTO position. This action sends a temporary ground signal to the BCM requesting a change of states for the ALC. If the ALC is currently ON it will switch to OFF, and if the ALC is currently OFF it will reset the ALC to ON.

The wiper activated headlamps feature is enabled anytime the ALC is enabled. When the front windshield wipers have been activated for approximately 30 seconds, and the ALC is in the DRL mode, the BCM will switch to headlamps ON.

The body control module (BCM) activates the lights ON warning as requested by the headlamp dimmer switch. The lights ON warning sounds when all of the following occurs:

The ambient light sensor is a light sensitive transistor that varies its signal to the body control module (BCM) in response to changes in the outside ambient light level. Any function or condition that turns ON the headlamps will cancel daytime running lamp (DRL) operation. With the headlamp switch in the OFF position, activating automatic lamp control (ALC), the front turn signal lamps will be turned ON after a 30-second delay under daylight conditions, which is determined by the ambient light sensor signal to the BCM. The DRL operates when the ignition switch is in the RUN position, the front wipers are not activated, and the transmission is not in PARK. When these conditions have been met and the ambient light sensor indicates daylight conditions, the BCM will illuminate the front turn signal lamps ON steady.

The PARK/LAMP fuse in the instrument panel (I/P) fuse block supplies battery positive voltage to both the coil and switch sides of the PRK LAMP relay, also located in the I/P fuse block. When the headlamp switch is placed in either the PARK or HEAD position, ground is supplied to the BCM on the park lamp switch ON signal circuit. The BCM then applies a ground to the park lamp relay control circuit. This energizes the relay, applying voltage to all park, tail, marker, and license lamps. The park, tail, marker, and license lamps are also turned ON when the headlamps are commanded ON by the BCM for low light operation.

Ground for the headlamp switch is from G200. Grounds for the various lamps are as follows:

When the remote function actuator (RFA) module receives a door unlock command from the remote function actuator transmitter, the RFA module will ground the door unlock signal circuit to the body control module (BCM), and send a class 2 message to the BCM, indicating that an UNLOCK command has been received. The BCM will then flash the park lamps twice. With all the doors closed, and the remote keyless entry (RKE) transmitter used to lock the doors, the park lamps will flash twice.

The STOP/TURN fuse in the instrument panel (I/P) fuse block supplies battery positive voltage to the body control module (BCM) for the turn signal lamps. When the turn switch is placed in the left or right position, ground is applied to the BCM on the left or right turn signal switch signal circuit. The BCM then applies voltage to the appropriate front and rear supply voltage circuits.

Grounds for the various lamps are as follows:

The hazard lamps switch is part of the multifunction switch on the steering column. When the hazard switch is pressed, a ground signal is applied to the body control module (BCM) on the hazard switch signal circuit. Hazard lamp operation is the same as the turn signals, with all turn signals operating simultaneously. The ground for the hazard switch is G200.

A chime or audio warning activates as a turn signal on warning if the turn signal remains ON for a specific distance traveled. The turn signal warning sounds when a turn signal remains active, and the vehicle has traveled a distance of 1.2 km (0.75 mi).

The driver information center (DIC) turns the turn signal reminder OFF when the ignition switch or turn signal switch is turned to the OFF position.

The turn signal lamps are also used as stop lamps. The STOP/TURN fuse in the instrument panel (I/P) fuse block supplies battery positive voltage to the body control module (BCM) for the stop lamps.

The brake pedal position sensor is a resistive device used to sense the action of the driver application of the brake pedal. The brake pedal position sensor provides an analog voltage signal that will increase as the brake pedal is pressed. The brake pedal position sensor receives a low reference signal and a 10-volt reference voltage from the body control module (BCM) to supply a variable signal input directly to the BCM on the brake pedal position sensor signal circuit when the brakes are applied. When the signal reaches a voltage threshold indicating the brakes have been applied, the BCM then applies a battery positive voltage to the left rear and right rear stop/turn lamp supply voltage circuits to illuminate the stop lamps in the tail lamp assemblies and to the stop lamp supply voltage circuit to illuminate the center high mounted stop lamp (CHMSL). The stop lamps will operate when the ignition switch is not in the OFF position.

The stop lamp supply voltage circuit also supplies the powertrain control module (PCM) and the electronic brake control module (EBCM) for other functions, and is from a separate pin in the BCM connector. A short to ground or voltage on this circuit will also cause the stop lamps to operate incorrectly.

The CHMSL BACKUP fuse in the instrument panel (I/P) fuse block supplies battery positive voltage to the body control module (BCM). When the driver places the gear selection into the REVERSE position, the powertrain control module (PCM) sends a class 2 message to the BCM. The message indicates that the gear selector lever is in the REVERSE position. The BCM then applies voltage to the backup lamp supply voltage circuit. Ground for the left backup lamps is from G401 and for the right backup lamp is from G400.

The body control module (BCM) controls the lighting system through circuits that enable headlamps and the courtesy lamps. If one of these lamps is left ON, battery rundown protection/inadvertent power feature will turn OFF the lamps 20 minutes after the ignition switch is turned to the OFF position. If the ignition switch is turned to any position other than OFF, or if a lamp is activated during this 20-minute period, the circuits will then be enabled.

If the headlamp switch is placed in the HEAD position after the ignition switch has been turned OFF, or if the ignition switch is in the ACCY position, the headlights will remain ON until turned OFF or the battery runs dead.