Ford Focus Service Manual: Exterior Lighting - Description and Operation

NOTE:

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

The exterior lighting system consists of the following components:

• Headlamp assemblies
• Fog lamps (if equipped)
• SJB (located under the instrument panel mounted left of the steering column)
• Stoplamp switch
• Headlamp switch
• Multifunction switch
• Reversing lamp switch (manual transaxle)
• High mounted stoplamp
• Rear lamp assemblies
• License plate lamps

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 feature.

The battery saver does not

control the parking lamps if the headlamp switch is in the PARKING LAMPS ON position.

Lamp Assembly Condensation

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. The headlamp assembly has the park/turn indicator and side marker lamp integrated into the headlamp assembly. The SJB supplies voltage to the headlamps when demanded on.

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

The front turn signal lamps are located within the headlamp assemblies. The rear lamps share functionality with the stoplamps (combination stop/turn lamps). When the multifunction switch is placed in the LH or RH TURN position, the SJB 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 flasher switch is integrated into the multifunction switch. When the hazard flasher switch is pressed, the SJB cycles the voltage on and off to all the turn lamps approximately 80 times per minute.

Parking Lamps

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

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

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 (integral to 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

The PCM receives input from the digital Transmission Range (TR) sensor (automatic transaxle) or the reversing lamp switch (manual transaxle).

When the transaxle is placed in REVERSE (R), the PCM 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.

Daytime Running Lamps (DRL)

If the SJB is configured for Daytime Running Lamps (DRL) , this feature illuminates the low beam headlamps at a reduced intensity when the following conditions exist:

• The ignition switch is in the RUN position.
• The headlamp switch is in the OFF position.
• The transmission is not in PARK (P) (automatic transaxle).
• The parking brake is not applied (manual transaxle).

The SJB can be configured to turn the DRL on for this vehicle. Refer to Section  418-01 for additional information on this programmable parameter.