Exterior lighting consists of the following lamps:

The headlamps consist of two interchangeable single filament bulbs which provide high and low beams. The inner bulb in the headlamp assembly is the high beam headlamp and the outer bulb is the low beam headlamp.

The headlamps may be turned on in three different ways:

During ALC control the headlamps will be in daytime running lamp (DRL) operation in daylight conditions, or low beam operation in low light conditions. A HEADLAMPS SUGGESTED message will appear on the driver information center (DIC) when the headlamps and park lamps are off due to all exterior lighting controls being inactive when nighttime conditions are sensed. The message will also appear if the wiper activated headlamps feature is off due to the twilight sentinel being off, but the windshield wipers are on. The Instrument Cluster (IPC) provides battery positive voltage to the headlamp switch signal circuit. The signal circuits include the headlamp switch signal circuit and the headlamp dimmer switch high beam signal circuit.

The headlamps are controlled by the body control module (BCM). The underhood fuse block provides battery positive voltage to the HEADLAMP relay switch through the HDLPS fuse. The rear compartment fuse block provides battery positive voltage to the HIGH/LOW BEAM HEADLAMP relay coil.

With the headlamp switch in the HEADLAMP position, the headlamp switch signal circuit is grounded through the headlamp switch to G205. In response to this input, the IPC sends a class 2 message to the BCM in order to activate the low beam headlamps. When the ignition switch is placed in the ON position The BCM provides battery positive voltage to the HEADLAMP relay coil. When the HEADLAMP relay coil is energized, current flows through the normally open contacts of the HIGH/LOW BEAM HEADLAMP relay switch to L HDLP LO fuse and the R HDLP LO fuse to the low beam headlamps. The low beam headlamps have ground at G101. When the ignition switch is in the RUN position, the twilight enable switch is on, and the IPC receives an input through the windshield wiper motor relay coil supply voltage circuit that the windshield wipers are on for approximately 20 seconds, the IPC will send a class 2 message to the BCM to activate the low beam headlamps. The wiper activated headlamp feature can be disabled by either turning the windshield wiper switch off, the twilight enable switch off, or by placing the ignition switch in the OFF position. The wiper activated headlamp feature will override the daytime running lamps (DRL). When the HIGH/LOW BEAM relay coil is energized, current flows through the L HDLP HI fuse and the R HDLP HI fuse to the high beam headlamps. The high beam headlamp ground circuit is divided into a left and right side. The current from the right high beam headlamp flows to ground at G101. The current from the right high beam headlamp flows through the DRL relay switch to ground at G101. The underhood fuse block provides battery positive voltage to the headlamp dimmer switch. When the turn signal lever is pulled toward the driver, the headlamp dimmer switch closes and the current flows through the headlamp dimmer switch high beam signal circuit to the IPC. In response to this input, the IPC sends a class 2 message to the BCM in order to energize the HIGH/LOW BEAM relay. The IPC also illuminates the high beam indicator when the high beam headlamps are requested. When the HIGH/LOW BEAM relay is energized, battery positive voltage is removed from the low beam headlamps causing the high beam headlamps to activate instead of the low beams. Both high beams remain on until the driver releases the switch handle. If the low beam headlamps were on during flash-to-pass operation, the headlamps will be switched to high beams. If the headlamp switch is left in the ON position, the inadvertent power control feature will turn off the headlamps 10 minutes after the ignition switch is turned to the OFF position. If the driver places the headlamp switch in the ON 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 cornering lamps are located in the park/turn signal lamp assembly. They are clear and illuminate the peripheral turn area of the vehicle. The cornering lamps will illuminate when all of the following conditions exist:

When the ignition switch is in the ON or START position, the underhood fuse block provides ignition positive voltage to the cornering lamps switch through the CNR LP fuse. When the turn signal switch is placed in the LEFT TURN or the RIGHT TURN position, ignition positive voltage is supplied to the appropriate cornering lamp from the turn signal switch. Both cornering lamps have ground at G101.

The daytime running lamps illuminate the high beam headlamps at a reduced intensity. The DRL will operate when all of the following conditions are present:

The BCM will not activate the daytime running lamps (DRL) feature if the headlamps have already been turned on through the headlamp switch or twilight sentinel. The ambient light sensor is a variable resistor that varies its voltage signal to the instrument cluster (IPC) in response to changes to the outside (ambient) light level. The value of the input voltage is between 0 and 5 volts. As the ambient light decreases, the resistance of the ambient light sensor increases. When the IPC receives this signal, the IPC sends a class 2 message in order to communicate the level of ambient light to the Body Control Module (BCM). When the twilight delay switch is moved out of the OFF position, the BCM either turns on the DRL or turns on the low beam headlamps, after a timed delay depending on whether daylight or low light conditions are sensed. The time delay is normally 8 - 20 seconds, and cannot be altered or adjusted. Any function or condition that turns on the headlights will cancel the DRL operation. The underhood fuse block provides ignition 1 voltage to the DRL relay coil through the IGN 1 fuse. The underhood fuse block also provides battery positive voltage to the DRL relay switch through the DRL fuse. When the ignition switch is in the RUN position, the ambient light sensor indicates daytime conditions, and the gear selector is not in the PARK position, a message is sent from the IPC to the BCM in order to activate the DRL. With the ignition switch in the RUN position, battery positive voltage is supplied to the DRL relay coil. When the BCM receives a message from the instrument cluster to activate the DRL, the BCM provides a ground to the DRL relay coil. The coil is then energized closing the normally open switch contacts. Battery positive voltage is then supplied through the DRL relay to the LH high beam headlamp and the RH high beam headlamp, which are in series. Ground is provided to both headlamps from G101. The LH and RH high beam headlamps will then illuminate at half intensity because they are in series.

The twilight sentinel system keeps the exterior lamps on for a pre-selected period of time after the ignition is turned off to improve night visibility when leaving the vehicle. The instrument cluster adjusts the twilight delay in 10 second intervals from 3 to 180 seconds in response to the voltage level at the twilight delay input. If the twilight sentinel is turned off during the delay period, the headlamps and the park lamps will turn off immediately. The lamps will be turned off automatically after the selected time period elapses from a few seconds to 3 minutes. The twilight delay switch in the headlamp switch assembly is supplied a 5 volt reference from the Instrument Cluster (IPC). The IPC also provides ground to the twilight delay switch. The switch is a potentiometer in which the resistance varies as the switch is moved. The IPC receives an input voltage proportional to the resistance of the potentiometer through the twilight delay signal circuit. The IPC sends a class 2 message to the BCM indicating the on/off status and delay length for the twilight sentinel. With the twilight sentinel switch in any position other than OFF, the BCM will turn the headlamps on or off according to the daytime/nighttime status sent by the IPC. The BCM uses the twilight delay signal in order to keep the headlamps and park lamps on after the ignition switch transitions from ON to OFF during nighttime conditions.

The fog lamp switch is a momentary switch that changes the fog lamp state from off to on or from on to off when pressed. The state of the fog lamps will remain the same until the fog lamp switch is pressed, even between ignition cycles. The fog lamps operate only when the ignition switch is in the ON or START position and the fog lamp state is on. The fog lamps will not illuminate when the high beam headlamps are on. When the fog lamps are on, the park lamps will also be activated. The FOG LAMPS ON indicator will also illuminate. The underhood fuse block provides ignition 1 voltage to the Fog Lamp Relay coil through the IGN 1 fuse. The underhood fuse block also provides battery positive voltage to the Fog Lamp Relay switch through the FOG fuse. When the ignition switch is in the RUN OR START position, and the fog lamps switch is enabled, the instrument cluster fog lamps input is grounded through the headlamp switch to G205. In response to this input the IPC sends a class 2 message to the BCM in order to activate the fog lamps. The BCM provides ground to the Fog Lamp Relay coil. The coil is then energized, closing the switch contacts. Battery positive voltage is then supplied to the fog lamps and the FOG LAMPS ON indicator. The BCM also activates the park lamps when the fog lamps are on. When the fog lamps are enabled and the high beams or flash-to-pass are activated, the front fog lamps will be temporarily disabled for as long as the high beams or flash-to-pass are enabled. The park lamps will remain on during this period.

The park lamps will illuminate when the headlamp switch is placed in the PARK or ON position. If the headlamp switch is left in the PARK or ON position, the park lamps will be deactivated after 10 minutes following an ignition switch transition to the OFF position, because of the battery rundown protection feature. The park lamps will also illuminate if the fog lamps are activated. When the park lamps are on the PARK LAMPS ON indicator illuminates. The side marker lamps illuminate whenever the park lamps are on. The side marker lamps contain reflectors for increased nighttime driving safety. The left underhood fuse block provides battery positive voltage to the PARK LAMPS Relay switch through the BODY 1 fuse. When the headlamp switch is in the PARKLAMP or HEADLAMP position, or the front fog lamps switch is enabled, the IPC park lamps input is grounded through the headlamp switch to G205. In response to this input, the instrument cluster sends a class 2 message to the BCM in order to activate the park lamps. The BCM provides battery positive voltage to the Park Lamps Relay coil. The Park Lamps Relay coil receives ground through the headlamp switch to G205. The Park Lamps Relay coil is then energized, closing the switch contacts. Battery positive voltage is then applied through the park lamps to the LT PARK Fuse and the RT PARK Fuse to the left and right park lamps.

When the twilight sentinel is activated and the ambient light sensor indicates darkness, the BCM applies battery positive voltage to the PARK LAMPS Relay coil. The BCM also provides ground for the PARK LAMPS Relay coil. The park lamps are then activated as previously described when activated from the headlamp switch.

When the remote function actuator (RFA) module receives a door LOCK or UNLOCK command from the remote function actuator transmitter, the RFA will send a class 2 message to the BCM in order to activate the Park Lamps Relay. The BCM must have inputs that indicate that the ignition switch is OFF, both doors are closed, and the ambient light sensor indicates low light conditions. The BCM will flash the park lamps, side marker lamps, and tail lamps once when the RFA module receives a door LOCK command from the remote function actuator transmitter, and twice when the RFA module receives a door UNLOCK command from the remote function actuator transmitter.

The turn lamps can only be activated with the ignition switch in the ON or START position. When the turn signal switch is placed in a position to indicate a left turn or a right turn, the respective turn signal lamps will flash. The respective turn signal indicator will also flash on the instrument cluster (IPC).

With the ignition switch in the RUN position, battery positive voltage is provided from the TURN Fuse, and through the turn signal flasher to the normally closed turn/hazard switch.

When the turn signal switch is placed in the LEFT TURN or the RIGHT TURN position, battery positive voltage is supplied through the turn signal switch and to the turn signal lamps. They begin to flash when the current heats up the timing element in the flasher and opens the switch. The turn signal flasher switch closes when the timing element cools. The flasher repeatedly opens and closes the circuit causing the turn lamps to flash. Battery positive voltage is applied from the HAZARD Fuse through the hazard flasher to the normally open turn/hazard switch. With the hazard switch in the HAZARD position, battery positive voltage is applied through the turn/hazard switch assembly to all four paths used by both front and rear turn lamps. All turn lamps and both indicators flash on and off. When in the HAZARD position, the turn signal circuit is opened within the turn/hazard switch and the flasher controls the lamps even if a turn has been indicated.

Battery positive voltage is provided from the STOP Fuse to the stop lamp switch. When the brake pedal is pressed, the stop lamp switch closes and battery positive voltage is provided through the stop lamp switch to the normally closed turn/hazard switch. Battery positive voltage is also provided to all tail/turn lamps and the high mounted stop lamp.

The underhood fuse/relay center provides battery positive voltage to both the REVERSE relay coil and switch through the PARK/REV fuse. When the gear selector is placed in the REVERSE position, the powertrain control module (PCM) sends a Class 2 message to the BCM. In response to this message, the BCM grounds the REVERSE relay coil, energizing the relay. The relay switch contacts close and battery positive voltage is supplied to the backup lamps. The backup lamps are permanently grounded at G402. The BCM will turn off the backup lamps if the ignition switch is turned to the OFF position or when the gear selector is moved out of the REVERSE position.

The underhood lamp is located in the engine compartment, on the left rear of the hood. When the park lamps are on, battery positive voltage is supplied to the underhood lamp. The underhood lamp has ground at G101. When the hood is opened, The switch in the underhood lamp closes and provides ground to the underhood lamp.

The underhood fuse block provides battery positive voltage to the Inadvertent Power relay coil through the MIRROR fuse. The left underhood fuse block provides battery positive voltage to the Inadvertent Power relay switch through the INADVERT fuse. When the ignition switch is turned to the RUN position, the body control module (BCM) will activate the inadvertent power relay by grounding the relay coil. When the inadvertent power relay is active, battery positive voltage is supplied to the underhood fuse block INT LPS Fuse, CIG LTR 1 Fuse, and CIG LTR 2 Fuse. The BCM will deactivate the inadvertent power relay ten minutes after the ignition switch is removed from the RUN position. With the ignition switch in the OFF or ACCY position, the BCM will also deactivate the inadvertent power relay ten minutes after any of the following conditions occur:

If the ignition switch is turned to any position other than OFF, or if a lamp switch is activated during this 10 minute period the timer will reset for another 10 minutes. This time is reduced to 3 minutes until the vehicle mileage is more than 22.5 km (14mi) +/- 2.2 km (1.4mi).