Exterior Lighting

WARNING: This page is about a different car, the 2010 Mercury Milan, 2010 Lincoln MKZ, and 2010 Ford Fusion. However, it is still accessible from the selected car via links, so may be relevant.

The SJB 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.

If the SJB does not detect any of the inputs to the headlamp switch is active (switched to ground) for 5 seconds, the SJB turns on the parking lamps and headlamps and keeps them on until the battery saver feature times out.

Additionally, if the SJB detects multiple headlamp switch input circuits short to ground, the SJB turns the parking lamps and headlamps on and keeps them on until the battery saver feature times out.

Refer to Battery Saver for information regarding the Battery Saver feature.

If either of the above situations occur, the SJB cannot be ruled immediately as being at fault. This is normal behavior of the SJB design as it has detected a fault with the inputs from the headlamp switch.

The SJB also monitors the multifunction switch for a flash-to-pass or high beam request. There are 2 voltage signal circuits which monitor this. When the multifunction switch is in the FLASH-TO-PASS or HIGH BEAM position, the voltage signal is routed to ground.

NOTE: The flash-to-pass feature does not require any input from the headlamp switch.

When the SJB receives an input requesting the headlamps on, the SJB supplies voltage to the low beam and high beam bulbs as necessary.