2006 Grand Marquis brake light oddities

Asked by Nov 22, 2014 at 04:24 PM about the 2006 Mercury Grand Marquis GS

Question type: Maintenance & Repair

Brake light (indicating emerg. brake on) had been coming on for a few days while I was
driving.  I added some brake fluid and that stopped.  Last night, the rear brake lights
stayed on after the car was shut off and I had to unhook the battery to stop that.  
Today I look under the dash to check on the cables, etc near the pedals, get out and
have my wife push the brake pedal.  Only brake light working now is the small one in
the back window.  What the heck is going on with this thing?

12 Answers


Lighting control modules are a factory defect. Look for rebuilt ones on EBAY. Might be something else, though, but sounds like your stoplight switch is working. I had to get a rebuilt LCM for my 2005 because the headlights stopped working. Ford payed for some of these, if it's documented. Should have been a recall.

1 of 1 people found this helpful.

Thanks for the response. I just remembered that the battery light had been coming on during the same period. Could that be related to any of this?

And the battery is less than a month old btw.


Maybe your alternator is bad? Voltage with the engine running should be over 14 volts.

Thanks, I will check that.

I measured while the car was running and it was mostly 14, though it flickered over to 13 occasionally.


That's adequate, 14.7 is ideal. Have you checked your brake light switch, high up on the pedal? Sometimes the wires break. I still think it's the LCM. I replaced my Wife's, and got a factory rebate. They go bad all the time.Try EBAY, lots of places rebuild them. Does the car go into drive OK? if the brake light switch is bad or broken wires, it's stuck in Park.

So Ford will reimburse me for the LCM if I buy it and put it in myself? How does the rebate work exactly?


I will have to ask my Wife, she took care of the paperwork. We ordered a rebuilt one from L.A. exchange, paid to have it installed because I'm too old to get under the dash anymore. I'll get back to you later, or Friday.

1 of 1 people found this helpful.

Thank you. I appreciate your help here.

Trippmeister on my 2007 grand Marquis the break lights are coming on but they shifter is still stuck in parkwhat do I do


If the lights were not coming on, it would be the stoplight switch. Since they do come on when you press the pedal, it has to be the interlock solonoid for the shifter. I don't know where it is, there are people on this site who know a lot more about that than I do. It's probably in the column. Have you made sure there are no broken wires at the stoplight switch? Happened twice on my '93.

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