what is a lighting control module and what does it look like on 2004 Mercury Grand Marquis

Asked by Mar 11, 2014 at 04:56 PM about the 2004 Mercury Grand Marquis

Question type: Maintenance & Repair

21 Answers



21 people found this helpful.


4 people found this helpful.

It's a black plastic box directly above the driver's right foot. It's held in place by two 7mm head / T-20 self-tapping screws. It has 3 or 4 connectors facing the firewall. The DLC is attached to the bracket holding the LCM in place. The LCM controls all of the lights in the car. It contains the chime for the key in ignition and lights left on. It shuts off the headlights and all other lights after (usually) 45 minutes of the engine being off. When the LCM fails, it usually causes the Headlights to flicker or go out completely. I think NAPA has an adapter that you can plug in instead of spending $250 - $300 on a new one.

13 people found this helpful.

If you think you have a bad LCM, there is 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. 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.

27 people found this helpful.

With a fleet of 800+ Crown Victoria PI's vintage 1999 to 2011, we probably replace 8 to 10 in a year. There was no sinister planning to make the vehicle more expensive to fix, the LCM does not have relays in it at all. BTW - it's also programmable. Not cheap junk designed to make Ford cars more expensive to repair.

2 people found this helpful.

Ok. Since you want to pick fights with me and the big Corporate monsters lurking in the shadows. Enjoy yourself. I have people to help instead of %$#* to talk to.

5 people found this helpful.

I am also trying to help. That is why I am posted here and elsewhere about Ford's decision to finally fix this LCM to the thousands upon thousands of retail Crown Vic. and Grand Marquis owners that have been victimized by it's unsafe design and to let them know that Ford through it's actions knows they have a MAJOR problem here. I only showed you the picture of the relays, after you told me that the LCM didn't have any. You inferred that I was being dishonest, and I used courtesy and tact to call you on it. You are not the only around who honestly wishes to help. Your latest response has been reported to the administrator as there should be a limit to someone who gets their ego bruised so easily that they won't admit when they have been wrong, and who casually infers others are being dishonest when they are just trying to help by sharing the truth.

8 people found this helpful.

There ARE 4 relays inside the LCM. I've repaired close to 200 of them already.

16 people found this helpful.

Yep And Ford DID play it cheap with these relays, or they wouldn't now be spending what they estimate to be $30 million to go back and fix their problem. Neither Ford or it's customers consider this a small problem. NOT AT ALL!!! Ford has gone so far as to blame some of their bad quarterly profit numbers on THIS LCM fix that it's furious customers have demanded. I have waited for pver a year on my TX dealer to get parts. one more driving ticket before a dist. judge and we will see who PAYS the FINE for inoperable hardware. BTW, no lights no PASS INSPECTION says judge. And Ford will have ot own WHY it doesnt pass.

1 people found this helpful.

Tracy, Here is a photo of the relays inside the standard LCM that you claim do not exist. Have you ever taken one apart and looked inside? I am a component-level electronics tech, and do not normally work on cars, unless it is my own, so maybe I just have a totally different way of looking at the problem. I haven't the financial luxury of ending my trouble-shooting at the "black box" level. Turn on the lights in a vehicle with a bad LCM and tap the case. Does that sound like a relay clicking, or a bad soldier joint/loose connector? It sure sounds like a relay to me... And Ford DID play it cheap with these relays, or they wouldn't now be spending what they estimate to be $30 million to go back and fix their problem. Neither Ford or it's customers consider this a small problem. NOT AT ALL!!! Ford has gone so far as to blame some of their bad quarterly profit numbers on THIS LCM fix that it's furious customers have demanded. Looking at the pictures of the LCM used in most police Crown Vic. Interceptors, they use five relays. (The extra one is for what is called "demand lighting".) It's possible the Interceptors got proper heavy-duty relays installed, but I can assure you the rest of us received unsafe junk for our $35,000, as even FORD has now been forced to admit.

12 people found this helpful.

My head lights do not come on, I checked all the fuses replaced whatever needs to be replaced the tail lights and side markers work but no headlights the only way the headlights work is if I pull back on the I believe it's called flash to pass lever then the head lights will be on however no other lights will be on. thank you for informing everyone about the LCM! I will be addressing this problem with for tomorrow and I will inform you of the outcome. Thank you

2 people found this helpful.

will a ford crown Victoria headlight control modular fit a 2000 mercury grand marquis

2 people found this helpful.

my mercury grand Marquet 2000 instumental lights are all out when i click the dim switch. what do you think the problem is??please answer.thanks

2 people found this helpful.

i have a 2000 grand marquis the front lights dont work but the back does the emergancy lights come on wen u.use the blinker an the horn wat the promblem


Cody, I experienced the same situation. I called Ford customer relations and even though they have not done a recall on this particular problem they did extend the warranty for certain cars and up to a certain mileage . My 2004 was part of that warranty . You need to prove it is the LCM before taking your vehicle to the dealership . Do this by tapping the LCM which is located approximately 18 inches from the floor along the gas pedal upward towards the dash comma there you will feel under the carpet a box Please call Ford Customer Relatiobs Center at 866- 436-7332 either they or the dealer can tell if you if your vehicle is covered to replace the LCM, or Lighting Control Modual. Have the VIN number( front left side of base of your dash in drivers side, read from outside of vehicle) available to give them.


Hi Cody! Please call the Ford Customer Relationship Center at 866 436-7332 either they or a dealer can tell you if your vehicle is covered by an extended warranty on the LCM, Lighting control module . You will need the VIN number available to give them. Its located on drivers side base of dash viewed from outside car. To test if it is the LCM... Approximately 18 inches up from the gas pedal on the right side, under the dash you will feel a box under the carpet, tap on it with your light switch on. If your lights come on that is your problem. That is a relay that you are tapping it will work to turn your lights on in that way for a little bit but eventually you will need to change your LCM. My lights went out while I was on the highway!! Very unsafe ! Please check out the explanation written by Ratpuppy....I am very appreciative of that write up! Wish you the best! Gidge

9/27/16 Ford dealership replaced LCM on my 2004 FCV b/c the lights came on only about half the time. Got home yesterday and the panic alarm went off about every 10-15 min. Turned car on and off, checked the blinking light on the dash was blinking and solid correctly, then no noise until almost exactly out 2 hrs later. On the way back to dealer (like I want to have work done by a dealer, right?) The car horn had randomly had rapid horn beeps a few time. After i dropped the key, it started panic alarm again. They Couldn't find the problem today but plan to replace the module again tomorrow. Very frustrating. We'll see what happens next. Loved the initial reply from the green team...probably a latent issue that came up... Really, just "happened" to occur after replacing LCM? And the "premier" maintenance team at a ford dealership can't figure out what's happening?. Very few dealership services have more effective technicians compared to my local repair shop, but where?


My headlights work fine, but I do have a few lighting issues on internal lights. None of my a/c lights come on, overhead light doesn't come on when I open door, my brake light is on but obd is telling me it's my airbag light. All of the obd codes give the answer to repair or replace LCM. I haven't tried the tapping it method, but I was thinking it could also just be a circuitry problem too yeah? Especially since my headlights seem to work fine. I just don't want to spend time effort and maybe money looking for shorts of the problem is just the lvm. This is for a 2004 Crown Vic PI

5 people found this helpful.

my interior lights go and off by themselves after a period of time when the car is parked turned off and the factory alarm is on

3 people found this helpful.

Would this be considered an LCM problem?

2 people found this helpful.

2000 grand marquis

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