Exterior Lighting

Exterior Lighting

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

NOTE: Cutaway and stripped chassis vehicles are supplied circuitry and connectors to support exterior lighting components.

The exterior lighting system consists of the following components:

- Headlamp assemblies
- Front parking/turn lamp assemblies (vehicles with sealed beam headlamps)
- Stoplamp switch
- Headlamp switch
- Multifunction switch
- High mounted stoplamp
- Rear lamp assemblies
- License plate lamps
- Trailer tow connector
- Trailer tow relays
- SJB (located under the instrument panel to the left of the brake pedal)

Battery Saver

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

The SJB provides automatic shut-off of the headlamps and parking lamps after a 10-minute time-out period in order to save battery voltage. A timer in the SJB is started when the ignition is turned to the OFF position and all the doors are closed. When 10 minutes have elapsed, voltage is automatically shut off to the lamps by the SJB. While the SJB has voltage disabled, the timer resets if any of the following occur:

- The ignition switch is placed in ACC, RUN or START positions.
- The headlamp switch is placed in the PARKING LAMP or HEADLAMP ON positions
- The multifunction switch is placed in the FLASH-TO-PASS position.
- The instrument panel dimmer switch is placed in the DOME LAMP position.
- Any button on the Remote Keyless Entry (RKE) transmitter (except LOCK) is pressed)

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. Clearing time can take as long as 48 hours under dry weather 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 may come 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.

Stoplamps

The stoplamp switch is located on the brake pedal assembly. The stoplamps 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 (on vehicles with OEM lamps), the SJB cycles the voltage on and off approximately 160 times per minute.

The hazard switch is part of the multifunction switch. 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 turn lamps share functionality with the stoplamps.

Parking Lamps

The SJB supplies voltage to the parking lamps when demanded. The parking lamp system includes the following:

- Front parking lamps
- Front side marker lamps
- Rear parking lamps
- License plate lamps

Reversing Lamps

When the transmission is placed in REVERSE (R), the PCM (all except 4.6L vehicles) or the Transmission Range (TR) sensor (4.6L vehicles only) 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 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 routed through BJB fuse 58 (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 description and operation or diagnostics of the factory manufactured trailer tow electric braking, refer to Auxiliary Brake System 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.

Vehicles not equipped with trailer tow require a Ford authorized accessory kit, if this option is to be added. Adding bulbs/lighting to existing circuits can cause the SJB to shut down the circuit and set a DTC due to the unexpected current flow.

Daytime Running Lamps (DRL)

The Daytime Running Lamps (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 SJB has a programmable parameter that can be configured to turn the DRL on for this vehicle. Refer to Module Configuration Special Tool(s) Used With Diagnostics for additional information on this programmable parameter.