Exterior Lighting

Exterior Lighting

NOTE: The Smart Junction Box (SJB) is also known as the Generic Electronic Module (GEM).

Battery Saver

NOTE: Time-out is 1 minute if the vehicle has less than 80 km (50 miles).

The battery saver is internal to the SJB and provides automatic shut-off of the headlamps and parking lamps after 10 minutes in order to save battery voltage. A timer is started when the ignition switch is turned to the OFF position with the headlamp switch in the HEADLAMPS ON position, or the headlamp switch is placed in the HEADLAMPS ON position with the ignition switch off. When the time-out period has elapsed, the voltage is automatically shut off to the lamps by the battery saver.

The battery saver does not control the parking lamps if the headlamp switch is in the PARKING LAMPS ON position.

Lamp Assembly Condensation

NOTE: Sealed-beam type headlamps are not vented. Any condensation within a sealed-beam type headlamp is unacceptable and the headlamp must be replaced.

Exterior lamps are vented to accommodate normal changes in pressure. Condensation can be a natural by-product of this design. When moist air enters the lamp assembly through the vents, there is a possibility that condensation can occur if the temperature is cold. When normal condensation occurs, a thin film of mist can form on the interior of the lens. The thin mist eventually clears and exits through the vents during normal operation. Time to clear the lens of acceptable mist varies with ambient humidity and lamp types. Normal condensation clears from any lamp in 48 hours under dry conditions.

Do NOT replace a lamp assembly with acceptable levels of condensation such as:

- presence of thin mist (no streaks, drip marks or droplets are present)
- fine mist covers less than 50% of the lens

Examples of unacceptable moisture (usually caused by a lamp housing leak):

- water puddling inside the lamp
- large water droplets, drip marks or streaks present on the interior of the lens

Headlamps

The headlamp system is a dual-beam pattern system. It consists of replaceable low/high beam bulbs. Vehicles can be equipped with aero-type headlamps, or sealed beam type headlamps.

The SJB supplies voltage to the headlamps when demanded. If the headlamps are on when the ignition switch is turned off, the battery saver feature turns off the headlamps after 10 minutes have elapsed.

Autolamps

The autolamp system provides light sensitive automatic on/off control of the exterior lamps. The autolamp system keeps the exterior lamps on for a pre-selected period of time after the ignition switch is turned to the OFF position (20 seconds is the factory default setting). The pre-selected time lapse is adjustable up to approximately 3 minutes. To change the autolamps time delay, refer to Autolamps Time Delay Adjustment Autolamps Time Delay Adjustment.

Headlamps On With Wipers On Feature

When the headlamp switch is in the AUTOLAMPS ON position and the front wipers are on for more than 3 seconds (except during a mist wipe or while the wipers are on to clear washer fluid during a wash condition), the exterior lamps are turned on. The exterior lamps are turned off when the ignition switch is changed to the OFF or ACC position, the headlamp switch is placed in the OFF position, or the front wipers are off for more than 30 seconds. The exception to this is when the exterior lights are on because of darkness determined by the light sensor.

Refer to Wiper and Washer Systems for diagnostics of the headlamps on with wipers on feature.

Stoplamps

The stoplamp switch is located on the brake pedal assembly. The rear lamps and high mounted stoplamp are supplied voltage when the brake pedal is applied. The rear lamps are combination stop/turn lamps.

Turn Signal/Hazard Lamps

When the multifunction switch is placed in the LH or RH TURN position, the SJB routes voltage to the LH or RH turn signal lamps. The SJB then cycles the voltage on and off approximately 80 times per minute. If a front or rear turn bulb is inoperative, the SJB cycles the voltage on and off approximately 160 times per minute.

The hazard switch is located on the center instrument panel finish panel. When the hazard switch is pressed, the SJB supplies voltage to all the turn lamps. The SJB cycles the voltage on and off approximately 80 times per minute.

On vehicles with aero-type headlamps, the park/turn indicator lamp is integrated into the headlamp assembly.

On vehicles with sealed-beam type headlamps, the park/turn indicator lamp is a separate assembly.

The rear lamps share functionality with the stoplamps.

Parking Lamps

The SJB supplies voltage to the parking lamps when demanded.

On vehicles with aero-type headlamps, the front park/turn indicator lamp and side lamp are integrated into the headlamp assembly.

On vehicles with sealed-beam type headlamps, the front park/turn indicator lamp is a separate assembly. The side lamp is also located within this assembly.

The rear parking lamps are located in the rear lamp assemblies.

Vehicles equipped with dual rear wheels have marker lamps located on the sides and rear of the pickup bed.

If equipped, the vehicle may have cab marker lamps located on the roof.

Fog Lamps

The fog lamp switch is integrated into the headlamp switch. When the fog lamp switch is engaged, the SJB provides ground for the fog lamp relay coil (integrated into the SJB), which then energizes and routes voltage to the fog lamps. The fog lamps can be turned on when the ignition switch is in the RUN or ACC position, the parking lamps are on, and the high beam headlamps are off.

Reversing Lamps

When the transmission is placed in REVERSE (R), the PCM (automatic transmission) or the reversing lamp switch (manual transmission) provides ground for the reversing lamp relay coil. The reversing lamps receive voltage when the reversing lamp relay is energized. The reversing lamps are located within the rear lamp assemblies.

Trailer Tow

The Battery Junction Box (BJB) supplies voltage to the trailer tow stop/turn, parking and reversing lamps. When the vehicle's rear stop/turn or parking lamps are illuminated, voltage is also supplied to a corresponding trailer tow relay (coil side) located in the BJB. When the reversing lamps are illuminated (the reversing lamp relay is energized), voltage is also routed through BJB fuse 63 (15A) to the trailer tow connector for the trailer reversing lamps.

The trailer tow battery charge relay provides voltage to the trailer tow connector when the ignition switch is in the RUN position.

The vehicle may be equipped with a factory manufactured trailer tow electric module. For diagnostic information, refer to Trailer Brake Control Module.

On vehicles not equipped with a factory manufactured trailer tow electric module, the vehicle comes equipped with circuitry to support trailer tow electric brakes.

Daytime Running Lamps (DRL)

The SJB can be configured to turn the Daytime Running Lamps (DRL) on for this vehicle. Refer to Information Bus for programmable parameter information.

The DRL system operates the low beam headlamps at a reduced intensity.

The SJB supplies pulse width modulated voltage to illuminate the low beam headlamps at a reduced intensity when the following conditions are met:

- The ignition switch is in the RUN position.
- The headlamps have not been turned on by the autolamp system or the headlamp switch.
- The transmission is not in PARK (P) (automatic transmission).
- The parking brake is not applied (manual transmission).