2005 Mercury Grand Marquis headlights, taillights, and brake lights dont work
Asked by RevTodd Aug 15, 2019 at 02:01 PM about the 2005 Mercury Grand Marquis GS
Question type: Maintenance & Repair
I just had the recall done on the control module thinking it would fix the
problem. It did not according to the Ford dealership. All fuses look good. I can't
afford to take it to a dealer, they said $190 just to diagnose!
7 Answers
What control module? There is a lighting control module. I just looked at info for your headlamps. Fixing one component may or may not fix the others? The headlamp switch signals the lcm and then the lcm acts accordingly. Sends voltage to multifunction switch for headlamps, hi and lo beam, that's how I understand it. There are trouble codes for your headlamps, manufacturer specific codes. Hopefully the diagram is correct.
The LCM had a recall. I just had it done. I wasn't driving the car but the person who was driving it said that the headlights stopped working all at once. I don't know if the brake lights stopped working at the same time or not. Either way, they none work. But the parking lights work and the blinkers work.
Are the headlamps automatic? Can you operate them manually? Using diagram check voltage and ground for lamps, top wire is voltage, bottom wire is ground. You can use a test light.
This all sounds beyond my capacity! I suppose I was looking to see if there is a part that would probably be the problem that I could replace with my limited knowledge of cars.
as far as where the problem is located, exactly, I'd have to do some testing. I don't think checking voltage and ground is beyond your capabilities. All you need is a test light.