System Operation - Headlamps, Expedition: Operation

WARNING: This page is about a different car, the 2017 Lincoln Navigator and 2017 Ford Expedition. However, it is still accessible from the selected car via links, so may be relevant.

Battery Saver

NOTE: The battery saver time-out is 1 minute if the vehicle has less than 201 km (125 mi).

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

To save battery voltage, the BCM provides automatic shut-off of the interior and exterior lamps after a time-out period when the ignition is off. The BCM monitors the ignition state and input from the RKE system to determine when to energize or de-energize the battery saver relay and to shut the power off to the lamps. A timer in the BCM starts when:

the ignition changes to OFF,
any door or liftgate becomes ajar while the ignition is off,
an UNLOCK button of the RKE transmitter is pressed while the ignition is off,
a valid keypad code is entered while the ignition is off,
or the instrument panel dimmer switch is used to turn the courtesy lamps on while the ignition is off.

When 10 minutes have elapsed, the BCM automatically shuts off voltage to the lamps. The timer restarts (voltage is restored if the BCM is in battery saver mode) if:

the ignition transitions out of OFF,
any door or liftgate becomes ajar,
the UNLOCK button of the RKE transmitter is pressed,
a valid keypad code is entered,
or the instrument panel dimmer switch is used to turn the courtesy lamps on.

Low Beams

The SCCM monitors the headlamp switch position by sending voltage signals on multiple circuits to the headlamp switch. There is one circuit for each headlamp switch position. At any given time, one of the signal circuits is switched to ground to indicate the headlamp switch position. The SCCM monitors the headlamp switch position and sends a headlamp switch status message over the HS-CAN to the BCM to indicate the headlamp switch status (position or a fault with the headlamp switch).

If the BCM detects a fault from the headlamp switch or loses communication with the SCCM, the BCM turns the parking lamps and headlamps on and keeps them on until the battery saver feature times out. If either situation occurs, the BCM cannot be ruled immediately as being at fault. This is normal behavior of the BCM design as a fault has been detected with the inputs from the headlamp switch.

When the BCM receives input requesting the headlamps on, it supplies voltage to the headlamp low beam bulb within each headlamp assembly.

The BCM also provides an overload protection of the low beam output circuits. When an excessive current draw is detected, the BCM disables the affected low beam circuit driver. REFER to Multifunction Electronic Modules .

High Beams

The SCCM monitors the LH steering column multifunction switch for a high beam or flash-to-pass request. When the LH steering column multifunction switch is in the HIGH BEAM or FLASH-TO-PASS position, the SCCM sends a Headlamp high beam flash to pass request message to the BCM over the HS-CAN indicating the request.

When the low beams are on and the BCM receives a request for high beams, the low beams remain powered and the high beams are activated. This adds light and changes the headlamp beam pattern to illuminate a greater distance.

The BCM also provides an overload protection of the high beam output circuits. When an excessive current draw is detected, the BCM disables the affected high beam circuit driver. REFER to Multifunction Electronic Modules .

Flash-To-Pass

When the low beams are off and the flash-to-pass is requested, the high beam bulbs are activated for approximately 0.5 second. When the low beams are on and the flash-to-pass is requested, the high beam bulbs are activated as long as the LH steering column multifunction switch is held in the FLASH-TO-PASS position.

Headlamp Exit Delay

When the ignition is OFF and the LH steering column multifunction switch is placed in the FLASH-TO-PASS position and released, the parking lamps and low beams are illuminated. They remain illuminated until:

3 minutes have elapsed with a door open.
30 seconds have elapsed after all doors are closed.
the LH steering column multifunction switch is placed in the FLASH-TO-PASS position again.
the ignition switches to RUN.

Within the 30 second delay and all the doors closed, opening any door results in the 3 minute timer restarting.