The exterior lighting consist of the following lamps:

The headlamps may be turned on in three different ways:

During ALC control the headlamps will be in day time 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 headlamps on signal circuit is grounded through the headlamp switch to G200. In response to this input, the DIM provides ground to the HDLP LO BM relay control circuit. The IPC illuminates the LIGHTS ON indicator when the DIM detects that the headlamps are requested. When the headlamp dimmer switch lever is pushed away from the driver to the HIGH BEAM position, the HDLP HI BM relay has ground through the headlamp dimmer switch. This Illuminates the high beam headlamps in addition to the low beams. The IPC illuminates the high beam indicator when the DIM detects that the high beam 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 headlamps have ground at G401. 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 circuit is divided into a left and right side circuit. The current flow of the left high beam is from the fuse to the left high beam lamp. From the lamp, the current flows to the normally-closed contact of the daytime running lamp (DRL) relay to G104. The current flow of the right high beam is from the fuse to the right high beam headlamp. From the lamp, the current flow is to ground at G401. 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. 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.

Normal operation of the HID system starts at the ballast. The headlamp ballast input connector receives the headlamp low beam supply voltage, which would normally be used to directly supply the low beam headlamp. Each ballast has a separate ground at G104. As soon as the input power is applied, the ballast draws 20 amps from the battery for 5-10 seconds (depending on the input voltage level). The ballast is then able to charge the two outputs leading to the start to -360 volts and +800 volts. -360 volts and +800 volts are the voltages needed by the starter to strike, or start, the lamp. HID headlamps do not have filaments like traditional bulbs. Instead, the starter uses a high-voltage transformer to convert the +800 volts input power into 25,000 volts. The increased voltage is used in order to create an arc between the electrodes in the bulb. The creation of this arc begins the start up process.

The DIM monitors the vehicle's system voltage while in the RUN power mode. When the system voltage drops below 8.9 volts, the following will occur:

STAGE 1: If the low beam headlamps are on, whether manually or automatically the DIM will turn ON the high beam headlamps by activating it's High Beam output.

When the system voltage drops below 8.5 volts, the following will occur:

If during the same ignition cycle, the DIM enters either STAGE 1 or STAGE 2 operations noted above, then determines that the system voltage has risen, the following will occur:

Ensure that the battery and the harness are capable of supplying up to 20 amps of current per ballast, with less than 2 volts of system loss or voltage drop. Each ballast requires the 20 amps in order to ensure normal startup and run up of the lamp. (Run up is the term used to describe the extra power level given to the bulb from the -360 volt ballast output.) The input current during the steady state operation in 3.4 amps at 12.8 volts.

After the lamp receives the strike from the starter and the arc is established, the ballast uses its -360 volt output in order to provide the run up power needed in order to keep the lamp on. The lamp rapidly increases in intensity from a dim glow to a very high-intensity, bright light called a steady state. Within 2 seconds of the arc being established in the bulb, 70% of steady state is complete. 100% of the steady state is completed within 30 seconds. A 75-watt power level is necessary in order to bring the lamp to a steady state in such a short period of time. The 75-watt power level allows the lamp to meet the SAE light vs. time specification.

Bulb failure (end of life) occurs when the bulb gets older and becomes unstable. The bulb may begin shutting itself off sporadically and unpredictably at first, perhaps only once during a 24-hour period. When the bulb begins shutting itself off occasionally, the ballast will automatically turn the bulb back on again within 0.5 seconds. The ballast will re-strike the bulb so quickly that the bulb may not appear to have shut off. As the bulb ages, the bulb may begin to shut off more frequently, eventually over 30 times per minute. When the bulb begins to shut off more frequently, the ballast receives excessive, repetitive current input (20 amp). Repetitive and excessive restarts or re-strikes, without time for the ballast to cool down, will permanently damage the ballast. As a safeguard, when repetitive re-strikes are detected, the ballast will not attempt to re-strike the lamp. The ballast then shuts down and the bulb goes out.

The following symptoms are the noticeable signs of bulb failure:

Input power to the ballast must be terminated in order to reset the ballast's fault circuitry. In order to terminate the input power to the ballast, turn the lights off and back on again. Turning the lights off and back on again resets all of the fault circuitry within the ballast until the next occurrence of excessive, repetitive bulb re-strikes. When excessive, repetitive bulb re-strikes occur, replace the starter/arc tube assembly. The ballast will begin the start-up process when the starter/arc tube assembly is replaced. Repeatedly resetting the input power can overheat the internal components and cause permanent damage to the ballast. Allow a few minutes of cool-down time in between reset attempts.

Bulb failures are often sporadic at first, and difficult to repeat. Technicians can identify bulb failure by observing if the problem gets progressively worse over the next 100 hours of operation.

White light has a different color rating than regular headlamps. The range of white light that is acceptable is broad when compared to halogens. Therefore, some variation in headlight coloring between the right and left headlamp will be normal. One HID at the end of the normal range may appear considerably different in color from one at the other end of the range. Difference in color is normal. Replace the arc tube only if the arc tube is determined to be at the bulb failure stage.

The cornering lamps are located in the headlamp 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 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 G401.

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 ambient light sensor indicates daytime conditions. The ambient light sensor is a light sensitive variable resistor that varies its resistance according to the level of (outside) ambient light. The IPM receives an input voltage proportional to the resistance of the ambient light sensor. 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 headlamp switch is in AUTO, the DIM either turns on the DRL or turns on the low beam headlights, after a 20 second delay depending on whether daylight or low light conditions are sensed. 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 to the left high beam. After the left high beam, the current flows through the HDHIBML fuse and through the HDHIBMR fuse. The current continues through the right high beam to ground G401. The high beam headlamps are now in series, which reduces the intensity. The DRL operate when the ignition switch is in the RUN position, and the parking brake is not set or the transmission is not in park. When these conditions have been met and the ambient light sensor indicates daytime conditions, the DRL will illuminate.

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 ambient light sensor indicates daytime conditions. Battery positive voltage is supplied from the rear fuse block EXPORT LGT fuse to the DRL relay coil and switch. When the Dash Integration Module (DIM) determines that conditions are present to activate the DRL, the DIM grounds the DRL relay coil. This energizes the DRL relay coil. Battery positive voltage is supplied through the DRL relay switch and to each low beam headlamp. The low beam headlamps have ground at G401. The park lamps will also illuminate.

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 front 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 FOG LP relay. Ignition voltage is available to the FOG LP relay coil. The Dash Integration Module (DIM) controls the FOG LP relay coil. When the front fog lamp switch is ON, 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 FOG LP relay, the current flows from the FOG LP relay switch to both front fog lamps. The front fog lamps have ground at G401. 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 be activated.

With the ignition switch in the ON or START position and the headlamps or the front fog lamps are on, the rear fog lamps will illuminate when the driver places the rear fog lamp switch in the ON position. The rear fog lamps will return to off between ignition cycles. If a flash-to-pass function is performed, the rear fog lamps will not turn off. The rear compartment relay center supplies battery positive voltage to the switch circuit of the RR FOG LP relay. Ignition voltage is available to the RR FOG LP relay coil. The Rear Integration Module (RIM) controls the RR FOG LP relay coil. When the rear fog lamp switch is placed in the ON position, the rear 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 RIM, which energizes the RR FOG LP relay. The IPC illuminates the rear fog lamp indicator when the IPC receives a class 2 message from the RIM after the rear fog lamps have been requested. When the RIM energizes the RR FOG LP relay, the current flows from the RR FOG LP relay switch to both rear fog lamps. The rear fog lamps have ground at G402.

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 signal circuit of the park lamp switch of the DIM has ground at G200. 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.

The position lamps are on export vehicles only. Each 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. 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 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 G401.

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 ambient light 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 flasher module. The module is part of the hazard switch assembly. The 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 flasher module. The 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 close 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 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 as described above. 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 driver presses the brake pedal, the switch contacts close. The battery positive voltage flows to the left stop lamp assemblies, to the right stop lamp assemblies, and to the center high mounted stop lamp (CHMSL). The left stop lamp and the CHMSL have ground at G402. The right stop lamp has ground at G401.

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.

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.

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.