Principles of Operation
WARNING: This page is about a different car, the 2009 Mercury Grand Marquis and 2009 Ford Crown Victoria. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
Due to varying wattage ratings and resulting current draw, certain aftermarket headlamp bulbs may cause the lighting control module (LCM) to shut down the short circuit protection, resulting in the low beams becoming inoperative. Verify that the headlamp bulbs meet Ford specifications.
The LCM receives inputs from the following:
- Headlamp switch
- Multifunction switch
Depending on the inputs received, the LCM commands the headlamps on or off.