Courtesy Lamps

WARNING: This page is about a different car, the 2015 Lincoln MKT. 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
LTM
Ignition state
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.

The LTM sends a 12-volt signal to the liftgate latch switch. When the liftgate is closed, the voltage signals are pulled low, indicating a closed liftgate. The LTM sends the tailgate status to the BCM by grounding the liftgate ajar circuit.

The BCM monitors input from the RKE transmitter, from the RFA module, to determine when to activate/deactivate the illuminated entry feature.

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

Based on the input, the BCM controls the solid state relays to provide power to the courtesy lamps.

The BCM also provides an overload protection of the interior courtesy and puddle lamp output circuits. When an excessive current draw is detected, the BCM disables the affected interior courtesy or puddle lamp circuit driver.