I have a 2005 Mercury Grand Marquis the other night noticed headlites did not seem to be on while driving home. Interior dash lites were on, turn signals were on, the corner lights were on just the headlites were not on.

By moving the high beam lever the high beam comes on but will not stay on. I have checked the fuse and it is good. I have installed a new headlight and no change.

With the lights in auto position all other lights come on. In manual all other lights come on. Problem is just with the headlights.

I am thinking the headlight switch is messed up but then I have heard some comments about a lighting control module. Dont know where that is at. Any advice appreciated...chuck

 

More than likely your LCM (lighting control module) has a failed relay.

You can get a 'rebuilt' module off eBay exchanged for a reasonable cost (about $200), or buy a new LCM from Ford for about $600.

You can also swap the LCM relay yourself if you are handy and can solder; see link below:

http://www.crownvic.net/ubbthreads/u...02#Post1437302

Let us know how you make out, Bill

 

Thanks for the info. I tried the link but I have to register first. I am waiting for approval. Just lucky we dont have to drive at night. So we can get by until I manage to get the car fixed. Thanks for your input...chuck

 

Go figure on this one. My wife just called me and said her headlight were working again. She had a little bear hanging off of the rear view mirror. She took it off and notice the convering needed straightening. She did that and the headlights work as they should. She locked the car with the remote and the headlights reacted as they should. We will check it out further when she gets home...chuck

 

I have a 2003 grand marquis and have the same problem as chuckjones. They would not come on, then they worked, now they do not work. The manual brights work. Was your problem ever resolved?

 

Funny about those headlights. My wife had a little animal (toy of course) hung from the rear view mirror. She removed it one day and messed with the wires going into the rear view mirror and the headlights started working again. Everything worked as it should. Then they quit again and we havent gone any further with the search. Hope this helps...it worked for a week or so...

 

Had a prob on 1998 GM with turn signals acting up, clicking irregularly, and similar prob with headlights. Finally replaced turn signal lever and wiper control assy! No more problems.. Hope this helps

 

I second the Lighting Control Module. It really sucks that all of those lighting elements have to run through such an expensive little box. Maybe you could go to a junkyard and pull one out of a wreck to try. Just convince the clerk it's a turn signal flasher, haha.

Best of luck

 

You can actually improve the front headlights brightness, and reliability by using a plug and play LCM by pass harness from SUV lights.com

There is just too much current for that little LCM to handle over long periods. It is underdesigned. The suvlights.com harness works in parallel with the LCM.

You LCM will last forever with this upgrade.

As soon as my 2009 Grand Marquis is out of the 3/36 warranty I am buying the suvlights.com harness.

Good Luck, Bill

 

Just a heads up to MGM owners regarding the Lighting Control Module (LCM). I 'd like to relate my experience with our 2010 GM bought late last year used w/57K miles. When purchased the interior lights, floor board lights, map lights, rear passenger reading lights, and interior trunk light did not work. Everything else worked - exterior lights, dashboard lights, horn, etc. Purchased an S&G Tool Aid #25100 Short Finder off ebay and some fuse "prongs" to see if I could find the "short". Slick little tool. Plugged it into the fuse slot for interior lights (LCM), F18 (15A fuse) - long story short, I could not find it.
After searching over the internet, came across Refurbished Light Control Modules: Ford Crown ,Mercury,Lincoln TownCar $89-90. (midwestteckmart.com) They indicated that one of the LCM symptoms was the interior lights do not work because the B+ connection is bad. They sell a rebuilt LCM with 4 year warranty - costs $80 + $120 core charge (refundable) + about $10 core return shipping charges. I rolled the dice, purchased one from them, installed it and Bam - everything is working. The 2010 GM LCM p/n is 8W7T13C788CA. This p/n is apparently good for 2008 up. The module I received from them was marked for a 2013 Lincoln Town Car, so it apparently works for that one also. Their LCM had the same p/n as mine. Replacing it was very easy, took about 15 minutes total time to remove and replace. They included instructions on removal. Move the driver seat back as far as possible. It's located to the right of the steering column, behind the dash, just above the OBD connector. Remove 2 7MM Hex Head screws, slide unit towards firewall and twist to left or right to clear the mounting bracket, the 4 cables are long enough to allow the unit to drop down to disengage the 4 connectors. Reverse the procedure for installation. Their instructions indicated some models have an outer plastic cover that is held in place with a couple of snapin/snapout plastic rivets, mine didn't. The hard part was lying on my back on the floorboard. Anyways, I hope this helps someone in resolving their lighting issues.