Courtesy Lamps

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.

The BCM controls all the interior lighting functions and timing by monitoring inputs from the:

Door ajar switches (integrated into the door latches)
Liftgate ajar switch (manual liftgate)
LTM (power liftgate)
Liftgate glass ajar switch
Ignition state
Courtesy lamp switch (integrated into the instrument panel dimmer switch)
RKE system
Vehicle speed

The BCM sends a 12 volt signal to each door ajar switch. When the doors are closed, the voltage signals are pulled low, indicating a closed door.

For vehicles equipped with a manual liftgate, the BCM sends a 12 volt signal to the liftgate glass actuator through the liftgate latch. When the liftgate and liftgate glass are closed, the voltage signal is pulled low, indicating a closed liftgate and liftgate glass. Opening either the liftgate or the liftgate glass will open the ground circuit.

For vehicles equipped with a power liftgate, the LTM sends a 12 volt signal to the liftgate glass ajar switch. When the liftgate glass is closed, the voltage signal is pulled low, indicating a closed liftgate glass. The BCM sends a 12 volt signal to the LTM. When the liftgate and liftgate glass are closed, the voltage signal is pulled low, indicating a closed liftgate and liftgate glass.

The BCM monitors the ignition state and inputs from the RKE system to determine when to energize the BCM courtesy lamps output. The BCM controls the voltage side of the courtesy lamps for the illuminated entry and exit features.

The SCCM monitors input from the instrument panel dimmer switch to determine the instrument panel dimmer switch position. If the SCCM determines that the instrument panel dimmer switch is in the COURTESY LAMPS ON position, the SCCM sends a courtesy lamp request message to the BCM over the HS-CAN and the BCM sends voltage to the courtesy lamps.

The BCM monitors the ignition state to determine when to activate/deactivate the illuminated exit feature.

The BCM also provides an overload protection of the interior courtesy and puddle lamp (Expedition only) or welcome mat lamps (Navigator only) output circuits. When an excessive current draw is detected, the BCM disables the affected interior courtesy or puddle lamp circuit driver. Refer to Multifunction Electronic Modules .