Exterior lighting consists of the following lamps:

The headlamps consist of two interchangeable single filament bulbs which provide high and low beams. The lower bulb in the headlamp is the high beam and the upper bulb is the low beam. these bulbs are also used for the daytime running lamp function.

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. When all exterior lighting controls are inactive and nighttime conditions are sensed, a HEADLAMPS SUGGESTED message will appear on the driver information center (DIC) after the IPC receives a class 2 message from the DIM. 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 dash integration module (DIM) provides battery positive voltage to the signal circuits of the headlamp switch. The signal circuits include the Head Lamp Switch input, and the Flash to Pass Switch.

With the headlamp switch in the ON position, the headlamp switch signal circuit is grounded through the headlamp switch to G201. In response to this input, the DIM provides ground to either the HDLP LO BM relay control circuit or the HDLP HI BM relay control circuit. The position of the dimmer switch determines which relay coil has ground. The IPC illuminates the LIGHTS ON indicator when the DIM detects that the headlamps are requested. The DIM supplies battery positive voltage to the relay coil circuits, if the headlamps are necessary. The underhood fuse block supplies battery positive voltage to both relay switch circuits. When the low beam relay coil is energized, current flows through the HDLOBML fuse and the HDLOBMR fuse to the low beam headlamps. The low beam headlamps have ground at G402. When the HDLP HI BM relay coil is energized, current flows through the HDHIBML fuse and the HDHIBMR fuse to the high beam headlamps. The high beam headlamps also have ground at G402. When the headlamp dimmer switch lever is pulled toward the driver, the Flash-To-Pass switch closes. This grounds the DIM Flash-To-Pass input. In response to this input, the DIM energizes the high beam relay. The IPC illuminates the high beam indicator when the DIM detects that the high beam headlamps are requested. 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 low beams remain on. The headlights may be switched to high beam with the opposite movement of the dimmer switch lever. All DeVilles exported to Norway, Sweden, Finland, or Isreal will operate so that the low beam headlamps will also remain illuminated when the dimmer switch is in the high beam position.

The cornering lamps are located just in front of the front wheels. 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 park lamps are on, battery positive voltage is supplied to the turn signal switch. When the turn signal switch is placed in the position to indicate a LH or RH turn, battery positive voltage is supplied to the appropriate cornering lamp from the turn signal switch. Both cornering lamps have ground at G104.

The daytime running lamps illuminate the low beam headlamps at a reduced intensity. With the daytime running lamps programmed to be on, the DRL will operate when the ignition switch is in the ON position, the gear selector is out of the PARK position, the headlamp switch is in the OFF position, and the sunload sensor indicates daytime conditions. The sunload sensor is a light sensor combined with two photodiodes used to calculate the ambient light condition. The sunload sensor shall provide a variable output current source to the IPM to monitor external lighting conditions. When the IPM receives this signal, the IPM sends a class 2 message to the DIM and to the rear integration module (RIM). When the twilight delay switch is moved out of the OFF position, the DIM either turns on the DRL or the low beam headlamps after a 20 second delay depending on whether daylight or low light conditions are sensed. For export Japan vehicles the DIM turns on the DRL or the low beam headlamps after a 3 second delay. Any function or condition that turns on the headlights will cancel the DRL operation. The DRL fuse in the underhood fuse block supplies battery positive voltage to the DRL relay switch. Battery positive voltage is also supplied to the DRL relay coil from the underhood fuse block which is energized by the DIM. When the DIM energizes the DRL relay coil, the current flows from the switch contacts of the DRL relay through the DRL resistor and to the left and right low beam headlamps.

The twilight delay switch in the headlamp switch assembly is supplied a 5 volt reference from the instrument panel integration module (IPM). The IPM also provides ground to the twilight delay switch. The switch is a potentiometer in which the resistance varies as the switch is moved. The IPM receives an input voltage proportional to the resistance of the potentiometer through the twilight delay signal circuit. The IPM sends a class 2 message to the dash integration module (DIM) indicating the on/off status and delay length for the twilight sentinel. With the twilight sentinel switch in any position other than OFF, the DIM will turn the headlamps on or off according to the daytime/nighttime status sent by the IPM. The DIM 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.

With the ignition switch in the ON or START position, the fog lamps will illuminate when the driver places the front fog lamp switch in the ON position. The front fog lamps will deactivate when the high beam headlamps are turned on. The underhood fuse block supplies battery positive voltage to the switch circuit of the front FOG LP relay. Ignition voltage is available to the FOG LP lamp relay coil. The Dash Integration Module (DIM) controls the FOG LP relay coil. When the front fog lamp switch is in the ON position, the front fog lamp input of the Instrument Panel Integration Module (IPM) has ground. In response to this input, the IPM sends a class 2 message to the DIM, which energizes the FOG LP relay. The IPC illuminates the front fog lamp indicator when the IPC receives a class 2 message from the DIM after the front fog lamps have been requested. When the DIM energizes the front FOG LP relay, the current flows from the FOG LP relay switch to both front fog lamps. The front fog lamps have ground at G402. The state of the front fog lamps (on or off) will remain the same until the front fog lamp switch is pressed again, even between ignition cycles. When the front fog lamps are on, the park lamps will also illuminate.

The tail, stop, and turn signal functions are performed by the quarter mounted tail lamps. The quarter mounted tail lamp consists of a red lens and light emitting diodes (LED) instead of incandescent bulbs. The quarter mounted tail lamp wraps around the corner of the vehicle and serves as the rear side marker. The lower portion of the lamp contains reflectors to alert approaching vehicles for nighttime driving safety. The park, tail, license and marker lamps are turned on when the headlamp switch is placed in the PARK LAMP or HEADLAMP position or anytime the headlights are requested. The park lamps are also turned on with the front fog lamps. When the ignition switch is in the ON position, the DIM provides battery positive voltage to the controlled positive voltage circuit of the PRK LP relay coil. The rear fuse block supplies battery positive voltage to the switch contacts of the PRK LP relay. When the headlamp switch is in the PARK LAMP or the HEADLAMP position, the park lamp switch on signal circuit has ground at G201. In response to this signal, the DIM provides ground to the control circuit of the PRK LP relay coil, which energizes the relay coil. This closes the relay switch contacts. Current flows from the PRK LP relay to the LP PK L fuse and to the LP PK R fuse. From the fuse, the current flows to the park lamps. The park lamps are grounded at G401 and G402. The DIMR fuse supplies battery positive voltage to the license lamps and to the DIM park lamp input, for interior lamps dimming. The license lamps are grounded at G402.

Each position lamp is located in the headlamp assembly. European countries require that side position lamps are activated when the vehicle is parked along the side of the road. The position function operates only when the gear selector is in the PARK position. If the gear selector is not in the PARK position, but the park lamps are on, the position lamps will operate as marker lamps. The front position lamp and respective tail lamp illuminate when the headlamp switch is placed in the left or right position. Battery positive voltage is supplied to the STANDING LP relay coil and switch. Battery positive voltage is supplied through the normally closed relay contacts of the STANDING LP relay switch to each POSN LP relay coil. When the gear selector is not in the PARK position, the dash integration module (DIM) grounds the STANDING LP relay coil which removes battery positive voltage from each POSN LP relay coil. The position lamps illuminate only when the ignition switch is in the OFF position. Battery positive voltage is supplied to each POSN LP relay switch. When the headlamp switch is placed in the RH PARK or the LH PARK position, the appropriate POSN LP relay coil is grounded through the headlamp switch contact. Battery positive voltage is then supplied to the appropriate position lamp and the respective tail/stop lamp. Both position lamps have ground at G104.

When the remote function actuator (RFA) module receives a door UNLOCK command from the remote function actuator transmitter, the RFA will send a class 2 message to the dash integration module (DIM). The DIM must have inputs that indicate that the ignition switch is OFF, all the doors are closed, and the sunload sensor is indicating low light conditions. The DIM will then activate the headlamp relay and park lamp relay. The DIM will flash the headlamps and park lamps twice, then keep them on approximately 25 seconds or until a door is opened. When the RFA module receives a door LOCK command from the remote function actuator transmitter, The DIM will flash the headlights and park lights once. In daylight conditions, the DIM will activate the park lamp relay only to flash the park lamps twice with a door UNLOCK command and once with a door LOCK command from the remote function actuator transmitter.

The TSIG/HAZ fuse in the rear fuse block supplies battery positive voltage to the turn signal/hazard flasher module. The turn signal/hazard flasher module has ground at G201. The turn signal lamps may only be activated with the ignition switch in the ON or START position. The IGN-1 fuse in the rear fuse block supplies battery positive voltage to the turn signal switch. When the turn signal switch is placed in either the left or right position, current flows from the turn signal switch assembly to the turn signal/hazard flasher module. The turn signal/hazard flasher module then sends an on-off voltage signal to either the left or right turn signals and their instrument cluster (IPC) indicator. When the hazard switch is pressed, the switch contacts are closed and the turn signal/hazard flasher module hazard input is grounded. In response to this input, the turn signal/hazard flasher module supplies battery positive voltage in an on and off flashing pattern to all the turn signal lamps. This also activates both turn signal indicators. When a THEFT is occurring, the Dash Integration Module (DIM) grounds the turn signal/hazard flasher module hazard input. The left turn signals have ground at G401 and at G402. The right turn signals have ground at G401.

The flash rate of the turn signal lamps is 90 flashes per minute. Each tail lamp assembly monitors the current among the LEDs. When 20 % or more of the tail lamp LEDs fail, that tail lamp removes ground from the outage detection signal circuit. The turn signal/hazard flasher module will then increase the flash rate of the remaining turn signal lamps and the respective indicator to 180 flashes per minute.

The repeater lamps are on export vehicles only. Each lamp is located in the front fender. The repeater lamps are used as additional turn signal lamps, and operate similarly. The repeater lamps have ground at G104.

The STOP LP fuse in the rear fuse block supplies battery positive voltage to the normally open stop lamp switch. When the brake pedal is pressed, the stop lamp switch contacts close and battery positive voltage is supplied to the center high mounted stop lamp (CHMSL) and the turn signal/hazard flasher module stop lamp switch signal input. In response to this input the turn signal/hazard flasher module supplies battery positive voltage to the left and right LED tail lamp assemblies. The CHMSL and left tail lamp have ground at G402. The right tail lamp has ground at G401. The stop lamps illuminate when they receive both power and ground.

The rear fuse block supplies battery positive voltage to the coil and to the switch terminals of the reverse lamp relay. Battery positive voltage to the switch terminal is available through the NSBU fuse. The dash integration module (DIM) sends a power mode message to the rear integration module (RIM) indicating that the ignition is in the ON position. When the driver places the gear selector in the REVERSE position, the powertrain control module (PCM) sends a class 2 message to the RIM. The message indicates that the gear selector lever is in the REVERSE position. The RIM then energizes the reverse lamp relay and the backup lamps illuminate. Current flows from the reverse lamp relay switch to the backup lamps. The backup lamps have ground at G402.

To provide battery run down protection, the exterior lamps will be deactivated automatically under certain conditions. The dash integration module (DIM) monitors the state of the headlamp switch. If the park or headlamp switch is ON when the ignition switch is placed in either the CRANK or RUN position and then placed in the OFF position, the DIM initiates a 10 minute timer. At the end of the 10 minutes, the DIM will turn off the control power output to the park and headlamp relay coils, deactivating the exterior lamps. This feature will be cancelled if any power mode other than OFF becomes active. The DIM will disable battery run down protection if any of the following conditions exist. The park or headlamp switch is placed in the ON to OFF position, and back to the ON position during battery run down protection. The DIM determined that the park or headlamp switch was not active when the ignition was turned OFF.