turn signals, head lamps, tail lamps, auto dome light not working. What is that about.


Asked by Dec 09, 2013 at 04:01 PM about the 2002 Mercury Grand Marquis LS Premium

Question type: Maintenance & Repair

The turn signals, automatic dome light, head lights and tail lights all refused to work upon starting my car this morning.  2002 Mercury Grand Marquis.  Can you help.  I can't find a fuse or relay that covers those items in my manual.

9 Answers


All of the lighting in your vehicle is controlled by the LCM (Lighting Control Nodule). There are fuses under the hood as well as under the dash above your left foot. The LCM is above your right foot (Black box with 3 connectors). The most common failure is the LCM although, I would test each fuse before condemning a $300 LCM.

10 of 10 people found this helpful.

Thank you Tracy for answering me so promptly. I will take the car to a garage tomorrow. Yuk! Merry Christmas.

1 of 1 people found this helpful.

You're very welcome!

1 of 1 people found this helpful.

It could very well be a fuse or LCM connector, HOWEVER if the problem is with the LCM itself: GOOD NEWS!!! Ford just started fixing them for FREE!!! (Ref: Ford Customer Satisfaction Program 14N01) Now you probably have a bad LCM if: Neither your low or high beams will come on, yet the "flash to pass" brights come on when you pull the light switch on the steering column towards you. That is the specific problem that Ford is addressing, yet your symptoms, if not a fuse or connector include this. Ford/Lincoln/Mercury has finally decided to deal with the rat-nasty LCM's they have been putting out. I just got the letter on this from Ford last week. Without starting a safety recall, (as they should,) they are extending the warranty on the LCM (based upon VIN number,) to 15 years or 250,000 miles whichever comes first. AND if you paid earlier for this replacement and have the receipt, they will reimburse you for the repair provided it was done before the notice came out. The window to be reimbursed for an earlier repair looks to be between April 1st, 2014 to October 31st, 2014. This window also applies if your car is under 15 years, yet has exceeded 250,000 miles. Ford's LCM replacement is completely without charge for parts and labor. Retail owners should have their VIN number handy and call the local dealership for an appointment. They say it should take a half a day yet could be longer due to dealer "service scheduling requirements." They will only replace LCM's that do not work, but mine lasted 10 years before it started acting up. This gives Ford a way to show concern, without really dealing with the 1000's of LCM's that will fail after this window closes in the future. Ford only "invented" their LCM after their service departments were losing money on a system that smaller repair shops could easily fix. Nice to have a little black box that they could unplug and swap out so they could charge $800-$1000 in parts and labor then repair at the factory with three $10 relays. Anyway if you have any questions about this "un-recall" you may contact the Ford Customer Relationship (I'm in a "relationship?") Center at 1 (866) 436-7332 either they or the dealer can tell if your vehicle is covered if you have the VIN number handy. IN THE MEANTIME. Should you need to get granny to the hospital at night, you can try this. The LCM on my 2003 is located about 18" directly above the gas pedal under the back of the dash... Turn on the lights and give the LCM a tap with your foot. This will often engage the cheap Ford relays and the lights will come on. But you should make that appointment with the dealer before everybody starts fighting for access to the same part. I also don't know if Ford would be willing to call someone a liar if he claimed his headlights stopped working because he thought it is just a matter of time before the lousy relays in his LCM failed, since this is intermittent, and asked for an LCM replacement under this warranty as well. That is why this should be a RECALL, and not just some bean-counter's way of slithering out from all of the angry customers that demand action today. My Grand Marquis is really a fantastic car, but having to drive 50 miles home on narrow country roads with one terrified hand while holding the "flash to pass" arm with the other, and risking my life because Ford played it cheap with some relays on their flagship chassis for a decade or more, really makes you wonder what they were thinking. If this could be covered under Ford's new extended warranty window for the LCM, then DO NOT TAKE IT TO A PRIVATE REPAIR SHOP!!! You will just be throwing your money away!

10 of 10 people found this helpful.

Copy and paste much?

3 of 3 people found this helpful.

Of course I am! I think it is very important to let as many people know about this un-advertised warranty extension as possible. Can you believe that there are actually shade-tree mechanics outside of the dealership network that know about this, yet are still charging loyal customers many $100s to replace these newly-warrantied LCMs? Can you imagine that? I am also cutting and pasting on other repair help sites. Maybe I will see you there as well! Happy Motoring!

3 of 3 people found this helpful.

Would this also cause the turn signals, ac, and rear view mirror nt to wrk?

2 of 2 people found this helpful.

My cars was replaced by and still don't work my mechanic got head lights and turn signals to work but tail light running lights don't engage what do I do my mechanic said they gave me a Chinese part and I looked at it my self

1 of 1 people found this helpful.

Thank you Thank You Thank You RatPuppy! I know it has been years since you posted this on here. However, your post saved a family I work with hundreds of dollars because their car still qualified!!! If it had not been for your post coming up on my search they would not be able to get their car fixed next week!

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