The exterior lighting include the following lamps:

The low beam headlamps may be turned on two different ways. First, when the headlamp switch is placed in the ON position. Second, with the headlamp switch placed in the OFF position and the ignition in RUN or CRANK position , during twilight sentinel operation in low light conditions. If the headlight switch is left in the ON position, the headlights are turned off after the ignition switch is turned to the OFF position. If however the headlights are turned on after the ignition switch has been turned OFF, the headlights will remain on until turned off or the battery runs dead. With the headlights in the low beam position, the high beams may be momentarily turned on or flashed with the dimmer switch handle. The flash-to-pass feature is accomplished by pulling the dimmer switch handle toward the driver. The high beams can only turned on when the low beams are operating. The high beams may be switched on by pushing the dimmer switch handle away from the driver until the dimmer switch is activated.

High Beams

The high beam headlamps are illuminated when all of the following relays are energized by the BCM.

1. Daytime running lamps (DRL) relay K131
2. Headlamp relay , LH (high beam) K73
3. Headlamp relay , RH (high beam) K132

The daytime running lamp relay K131 has battery voltage supplied at all times to the switch side of the relay and the coil side of the relay. When the daytime running lamp relay K131 is pulled low by the BCM the relay energizes, the relay's internal switch closes and battery voltage is supplied to the LH high beam lamp. The LH headlamp relay K73 has ground supplied at all times to the switch side of the relay and battery voltage supplied at all times to the coil side of the relay. When the LH headlamp Relay K73 is pulled low by the BCM the relay energizes, the relay's internal switch closes and ground is supplied to the LH headlamp and it illuminates.

The RH headlamp relay K132 has battery voltage supplied at all times to the switch side of the relay and the coil side of the relay. When the RH headlamp relay K132 is pulled low by the BCM the relay energizes, the relay internal switch closes and battery voltage is supplied to the RH headlamp. The RH headlamp is grounded at all times by G103 and the RH headlamp illuminates.

The high beam headlamps can only be turned on when the low beam headlamps are on. The BCM will energize the RH and LH headlamp relays and the daytime running lamp relay when the BCM receives battery voltage from the high beam switch. The LO BEAM Fuse supplies voltage to the turn signal switch only when the low beam headlamps are on. When the turn signal lever is pushed forward, the turn signal switch sends battery voltage to the BCM. When the BCM receives battery voltage from the turn signal switch, it then pulls low the daytime running lamp relay K131 and the LH and RH headlamp relays. The coil side of the relays have battery voltage supplied to them at all times and the relays energize.

Low Beam

When the headlamp switch is in the HEAD position it sends a ground signal to the BCM. The BCM receives the ground signal from the headlamp switch and then sends a ground signal to relay coil of the low beam relay. The headlamp switch also sends a redundant ground signal to relay coil of the low beam relay .

The low beam headlamps are controlled by the low beam relay (K131). The supply voltage for the coil side of the low beam relay is supplied from the BCM exterior lamp power circuit. The low beam relay coil is controlled by a ground from the BCM or the headlamp switch. When the BCM or the headlamp switch grounds relay coil of the low beam relay , the low beam relay coil is energized and the low beam relay internal switch closes.

The low beam relay has battery voltage supplied at all times to the switch side of the relay. When the low beam relay is energized, the internal switch closes and battery voltage is supplied to fuse  #22 and fuse  #31. Fuse  #22 supplies battery voltage to the LH low beam headlamp and fuse  #31 supplies battery voltage to the RH low beam headlamp. The LH and RH low beam headlamps are permanently grounded to G103. When battery voltage is applied to the headlamp supply voltage circuit of the LH and RH low beam headlamps, both of the headlamps illuminate.

Headlamps w/High Intensity Discharge (HID)

HID headlamps are optional. 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. As soon as the input power is applied, the ballast will charge for a brief time, depending on the input voltage level. The ballast is then able to charge the two outputs to the voltage level 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 input power into a higher voltage. 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.

Run Up Of The Lamp (w/HID)

Each ballast requires higher amperage 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. The input current during the steady state operation is lower that the start up amperage. After the lamp receives the strike from the starter and the arc is established, the ballast uses its operating voltage 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 a few seconds of the arc being established in the bulb, the majority of steady state is complete. 100% of the steady state is completed shortly there after. A high watt power level is necessary in order to bring the lamp to a steady state in such a short period of time. The high watt power level allows the lamp to meet the SAE light vs. time specification.

When To Change The HID Bulb

Bulb failure, end of life occurs when the bulb gets old 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 . 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.

Light Color (w/HID)

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 flash to pass feature will operate the high beam headlamps whether the low beam headlamps are ON or OFF. The flash to pass switch has battery voltage supplied to it at all times. Pulling the turn signal lever toward the driver will close the flash to pass switch, sending battery voltage to the BCM. When the BCM receives the flash to pass signal it will energize the RH and LH headlamp relays and the daytime running lamp relay, turning ON the high beam headlamps.

The daytime running lamps (DRL) illuminate the high beam headlights at a reduced intensity. When the headlight switch in the OFF position, ignition switch is in the ON position, and the transmission is shifted out of the PARK position, the high beam headlights will either be turned ON or OFF, after an approximate 30 second delay depending on whether daylight or low light conditions are sensed. When these conditions have been met and the ambient light sensor indicates daytime conditions, the DRL will illuminate. Any function or condition that turns on the headlights will cancel the daytime running lamps operation.

Voltage is applied to the DRL relay at all times. The BCM sends a ground signal to the DRL relay coil when the ignition is in the ON position and the transmission is shifted out of the PARK position, energizing the DRL relay. When the DRL relay is energized, voltage is applied to the LH high beam headlamp. The LH high beam headlamp is wired in series with the RH high beam headlamp and the high beam headlamps illuminate at a reduced intensity. When the headlamp switch is in the HEAD or PARK position, the BCM will not energize the DRL relay.

The Twilight Sentinel (TS) is a BCM feature that will turn on the low beam headlamps and the park lamps and adjust the interior lighting. This is accomplished when the ignition switch is in the ON position and the headlamp automatic control ambient light sensor indicates darkness.

There is a fixed delay of 2 seconds transition from day to night illumination, and a fixed delay of 40 seconds transition from night to day illumination. In addition, there is an added variable delay which can be adjusted from 10 seconds to 180 seconds.

The twilight sentinel indicator is also controlled by the BCM. Battery voltage is supplied to the twilight sentinel indicator by fuse #15. When the twilight sentinel switch is turned to the OFF position, the BCM internally grounds the TS indicator circuit of the BCM. This provides a ground to illuminate the twilight sentinel OFF indicator.

The headlamps required indicator in the instrument cluster will be turned on by the BCM if the ignition is on and the following conditions are met:

When the ignition switch is in the ON position and the wipers have been turned on for approximately 20 seconds, the BCM will turn on the low beam headlamps and the park lamps. The low beam headlamps and the park lamps will turn off approximately 20 seconds after the wipers have been turned off. If the ignition switch is turned to the LOCK position, the low beam headlamps and the park lamps will immediately be turned off.

When the driver presses the fog lamp switch with the ignition switch in the ON or ACCY position, and the park lamps or low beam headlights are ON, the front fog lights will illuminate. The state of the fog lamps (on or off) will remain the same until the front fog lamp switch is pressed again. The park lamps or low beam headlights must be ON in order for the fog lights to be illuminated. The front fog lamp operation will be cancelled whenever the high beam headlights have been selected.

Voltage is supplied to the internal switch of the fog lamp relay through the RH high beam headlamp relay K132 with the high beams headlamps off. When the ignition switch is in the ON position, battery voltage is applied to internal logic of the fog lamp relay. When the park lamps are ON, battery voltage is applied to coil side of the fog lamp relay. When the fog lamp switch is turned to the ON position, ground is supplied to the relay coil of the fog lamp relay and the fog lamp relay energizes. when the fog lamp relay energizes the fog lamp relay outputs battery voltage to the fog lamps and fog lamp indicator. Both of the fog lamps are permanently grounded to G103.

The park, tail, marker lamps, and license lamps, are turned on when the headlamp switch is placed in the PARK or HEAD position or anytime the headlights are requested. The exterior lights power control feature prevents the park lights from remaining on if inadvertently left on. If the park lights are turned on after the ignition switch has been turned OFF, or is in the ACCY position, they will remain on until turned off or the battery runs dead.

The BCM supplies voltage to the park lamp relay coil via the exterior lamps power circuit. The park lamps are operated by the headlamp switch or twilight sentinel feature. When the headlamp switch is in the PARK position it sends a ground signal to the BCM. The BCM receives the ground signal from the headlamp switch and then sends a ground signal to the relay coil of the park lamp relay K130 energizing the relay. The headlamp switch also sends a redundant ground signal to the park lamp relay K130.

Fused battery voltage is supplied at all times to park lamp relay internal switch contacts. When the park lamp relay K130 is energized the internal switch closes. The park lamp relay supplies battery voltage is to fuses #23, #26 and #30. Fuse #23 supplies battery voltage to the LH park lamp and the LH outside tail lamp. Fuse #30 supplies battery voltage to the RH park lamp and the RH outside tail lamp. Fuse #26 supplies battery voltage to the LH and RH front side marker lamps; the LH and RH rear license lamps; and the LH and RH inside tail lamps.

The LH and RH park/turn signal lamps are permanently grounded to G103. The inside tail lamps, outside tail lamps, rear license lamps are permanently grounded to G400. The LH front side marker lamps are grounded in series parallel with the LH front turn signal lamp and the RH rear turn signal lamps. The RH front side marker lamps are grounded in series parallel with the RH front turn signal lamp and the RH rear turn signal lamp.

All of the exterior lamps (including the front side marker lamps) will illuminate when the park lamp relay is energized. Because, the front side marker lamps are wired in series with the turn signal lamps they will not illuminate when battery voltage is applied to the turn signal lamps (during turn signal operation). When the turn signals flash the front marker lamps will not illuminate and then resume illumination when the turn is not operating.

The turn signal lamps are activated with the ignition switch in the ON or ACCY position. When the turn signal switch lever is placed in either the left or right position, the respective turn signal lamps will flash. The respective instrument cluster (IPC) turn signal indicator, either left or right will also flash.

Fuse #3 supplies battery voltage to the turn signal lamp flasher K10 through the hazard warning switch. When the turn signal switch is engaged to the "TURN LEFT" position, pulsating voltage is supplied from the turn signal lamp flasher K10 to the LH turn indicator, to the LH park/turn signal lamp and to the LH rear turn signal through the turn signal switch. When the turn signal switch is engaged to the "TURN RIGHT" position, pulsating voltage is supplied from the turn signal lamp flasher K10 to the RH turn indicator, to the RH park/turn signal lamp and to the RH rear turn signal through the turn signal switch. The LH and RH turn indicators are permanently grounded within the instrument cluster to G103. The LH and RH park/turn signal lamps are permanently grounded to G103. The LH and RH rear turn signals are permanently grounded to G400.

When the hazard switch is pressed, all turn signal lamps will flash including both IPC turn signal indicators.

Fuse #12 supplies battery voltage to the hazard warning switch at all times. When the hazard warning switch is pressed to the ON position, pulsating voltage is supplied from the turn signal lamp flasher K10 to the LH and RH turn indicators, to the LH and RH park/turn signal lamps and to the LH and RH rear turn signals through the hazard warning switch. The LH and RH turn indicators are permanently grounded within the instrument cluster to G103. The LH and RH park/turn signal lamps are permanently grounded to G103. The LH and RH rear turn signals are permanently grounded to G400.

When the driver presses the brake pedal, all stop lamps and the auxiliary brake warning lamp will illuminate.

Fuse #12 supplies battery voltage to the stoplamp switch at all times. When the brake pedal is pressed, the stoplamp switch supplies battery voltage to the LH and RH stoplamps and the auxiliary brake lamp. The LH and RH stoplamps and the auxiliary brake lamp are permanently grounded to G400.

When the low beam relay K131 is energized, battery voltage is supplied to fuse #31. Fuse #31 supplies battery voltage to the turn signal switch. When the turn signal switch is engaged to the "TURN RIGHT" position, battery voltage is supplied to the RH cornering lamp through the turn signal switch. When the turn signal switch is engaged to the "TURN LEFT" position, battery voltage is supplied to the LH cornering lamp through the turn signal switch. The LH and RH cornering lamps are permanently grounded to G103.

With the ignition switch in the ON position and the driver selects the REVERSE position, the automatic transmission range switch will illuminate the backup lamps.

When the ignition switch is in the ON position, battery voltage is supplied to fuse #3. Fuse #3 supplies battery voltage to the automatic transmission range switch. When the automatic transmission control lever is moved to the REVERSE position, battery voltage is supplied to the LH and RH backup lamps through the automatic transmission range switch. The backup lamps are permanently grounded to G400.

Fog Lamp

The IPC illuminates the fog lamp indicator when the malfunction relay K134 detects that the fog lamps are requested (signal is low) from the multifunction relay K134.

Headlamp On Required

The IPC illuminates the headlamp on required indicator when the ambient light sensor detects it is dark enough outside that the headlamps and/or other exterior lamps are required. The BCM sends a hardwire (signal is low) output to the IPC.

High Beam

The IPC illuminates the high beam indicator when the body control module (BCM) detects that the high beams are requested (signal is low).

Turn Signals

The IPC illuminates the right or left turn signal indicator when the IPC detects a turn signal request or a hazard request.

The Body Control Module (BCM) module processes the inputs and the controls. The ambient light sensor supplies the BCM with a signal for daytime conditions or for low light conditions.

Driver controls include the following components.