2002 Mercury Grand Marquis Q&A
2002 Mercury Grand Marquis Question: why will the front lights not turn on when the car is on.
There's an auto headlight module in this car which could be faulty. There's also a 'multi-function switch' involved. Best thing is check first at the headlight connectors with a meter or a testlight to see if there's power and ground at the bulb connectors. If there's power and ground, the bulbs are bad. If no ground, trace the circuit to the ground points. If no power, the fault is in the system. You may want a Ford/Merc specialist or an auto electric shop to check this out. Here's a directory link for you: https://repairpal.com/directory?address=34221&car_brand_names=Mercury - Superbob