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Ford Crown Victoria/Mercury Grand Marquis Electrical/Lighting



  • Thanks for the response! I just had the headlight switch replaced this week (90 bucks) and the same problem occurred this weekend again. I have a feeling it is the automatic light sensor. I don't know how costly it will be, I just rolled over 50,000 on my 2004 FCV. :confuse:
  • I'm sorry that your car is possessed. It sounds like you have something kicking up the juice and something trying to stop that, hence the flickering. The regulator is in the alternator so it is behaving schizoid. You have a short in your wiring somewhere that is barely visible if at all to the naked eye and that's why it is so hard to find. We used too have a place in Rockford that would go over your wiring with a fine tooth comb and find such a thing. That is the kind of place you need to look for if you don't have time to ckeck each wire yourself and don't want to take it to the dealer... who might send it there anyway.
  • I have a 92 crown vic and the headlights come on but no instrument or tail lights, I replaced the headlight switch but still having the same problems.....any suggestions?
  • The problem with the Marquis among other vehicles is that the fuses aren't named on the fuse box; so you need the operator's manual to check them. I'm guessing you have a blown fuse. If not you might have a blown tail light bulb.
  • All my lights &blinkers work except the rear driving lights.It has burned the switch wire & plastic switch cover although all other work fine.I wold like to find out what is wrong before i buy a new Switch so it does not happen again.Is it in the switch or somewhere else&where would i find it.Please help!!!
  • We never solved it until we changed the headlight switch AND the wires that got to the switch as far up as you can change them.
  • Hey everyone, new member here. I have a 2009 GM LS & it has automatic day running lights. Every time I start the car the headlights come on automatically.
    I don't like running around with my headlights on, can I shut them off so they don't come on until I turn the headlights when I want them on ?
    If so, could someone please walk me through it with instructions.

    Thank you,
    Great site & all of you helping each other is great thing..

    Thanks again
  • euphoniumeuphonium Great Northwest, West of the Cascades.Posts: 3,425
    And what does your Owner Manual advise? Could be you don't have a choice. ;)
  • I know what you mean about that. I hate them myself. You could always try unplugging them from the bulb at the socket; if everything else still works after you do.
  • I have what appear to be multiple power drain issues through the Power Distribution Box.

    By trial & error, I have identified the following:

    MAXI 14 causes Relay 1 to click, slight power drain.
    MAXI 11 pulsing power drain...approx 2 second cycle.
    Circuit Breaker 7 flashes bright, then steady moderate power drain.
    Standard 5 causes Relay 2 to click, then slight power drain.
    Standard 3 glows bright, definite power drain.

    There were no problems until the external temperature sensor started telling me it was 90 degrees out during a blinding snowstorm. After I replaced that unit, the vehicle battery went dead on me. After replacing a (new) battery - less than a year old - under warranty, and then having its replacement also go dead on me after about a month, I started the circuit checks.

    Before I tear the car apart, can anyone who knows more than I look at my power drain findings and perhaps tell me things about the direction(s) I should take on this one?
  • I don't know what the readings on these relay and circuit breakers are supposed to be, but I do know that your on board computer is properly reacting to one or more bad sensors. Test the sensors if you can and you will find the problem.
  • njadamsnjadams Posts: 3
    I have a 2003 Grand Marquis that I really enjoy driving. Within the past month the headlights go off while I am driving without hitting a bump in the road to cause a loose wire to move. Sometimes they come back on but go out again within a few minutes. The flashers work and so do the brights if I hold them on, but if I put the bright lights on, they do not work, either. Can anyone tell me what the problem is?
  • If you find any answer to this problem please ,please let me know . I have had to drive my car either in the daytime or if at night holding the brights on. I went to a mechanic and he quoted me a price of $500 to fix it but could not tell me what he was going to do. Yeah right. So still waiting to see if anyone knows what will fix it.
  • Yes. When we had that same problem we replaced the light switch in the dash. You must also replace the wires as far back as you can. And use a good crimping tool because you must have a solid connection. My personal belief is that Mercury has too much going through that switch.
  • fordgirl4fordgirl4 Posts: 3
    My dom lights on my 99 crown vic keep coming on and going off while vehicle is parked and doors are locked or unlocked. If I have headlights on auto, they come on with the dom lights. Does anyone know what I can do to solve this problem? I have had to replace on battery already.....working on second one.
  • pmitchellppmitchellp Posts: 19
    Yes, it is the notorious power-busting lights switch in the dash that strikes again! We had to replace the switch along with the wires back as far as we could to finally stop the problem.
  • fordgirl4fordgirl4 Posts: 3
    What is that switch called if you know pmitchellp? Thanks for helping me! fordgirl4
  • coltraincoltrain Posts: 1
  • pmitchellppmitchellp Posts: 19
    Yes, that would still be the light switch in the dash that has to be replaced along with the wires. It has the 'delay' function incorporated in it.
  • neeciep1neeciep1 Posts: 1
    I'm having a similar problem with my headlights :cry: and took it to a repair shop. They diagnoised it as a headlight module problem that has to be replaced. The replacement part is a dealer only and they have to order the part, which costs $500. They first had to determine what the problem at $92 an hour! It looks like this is going to cost me $800 just to see at night. OUCH!!!
  • njadamsnjadams Posts: 3
    That is what my problem was and I was quoted about the same prices. I searched the web and so did a friend of mine and we came up with a website that will send you a repaired one when you send them yours and it only costs about $99.00. We did this and everything is working fine now.
  • davelaterdavelater Posts: 2
    Dealer reports I need new lighting control module YW7Z13C788CA to remedy turn signal problem. Lights work fine. Both turn signals work fine when engaged, but the "clicker" sound occurs randomly when the turn signal lever is in the neutral position, sometimes fast sometimes slow. No bulbs are missing, all work. Any advice to find a remedy? Replacement costs is $850 with labor. Is there a secondary market for working used modules? I want to keep the car because miles are low and it's in good shape, but ouch the cost of this one is high.
  • euphoniumeuphonium Great Northwest, West of the Cascades.Posts: 3,425
    Consider an independent auto electrical repair shop with either remanufactured or donor parts from a wrecking yard. Of course, bench test the replacement part 1st.
  • dudatdudat Posts: 3
    My headlights and cornering lights will not come on when the headlight switch is on. The "Flash to Pass" works to bring on the high beams. Then after an undetermined time I hear a relay click in the Lighting Control Module and the headlights and cornering lights start working. I have noticed that the headlight switch has been warm to the touch. All other lighting functions work normally. Any ideas as to whether it is the Lighting Control Module, the Multifunction Switch or the Headlight Switch?
  • dudatdudat Posts: 3
    I believe the Lighting Control Module is programmable so be sure that any used one is from the same model with the same lighting functions.
  • ant97cvant97cv Posts: 1
    I've had that with my 97 crown vic for the last year, and yeah it's getting worse. Now, if I turn off the AC, the digital display for the ac will flick light up the entire lcd and click repeatedly if i'm over 40mph. turning the ac on low keeps the voltage spike down some. The problem got a lot worse after I had a auto start installed by a non-dealer. had to ahve that taken out in the end. I've tried replacing the alternator, belts, spark plugs, and battery. None of that helps. It sounds like the problem may be wiring hooked into the light control module under the dash by the break pedal as described here haven't checked those wires yet, reallt not looking forward to replacing the lcm they run anywhere from 90 - 300$. Recently fried the turn signal module and electronic trunk release module.
  • hdave7hdave7 Posts: 9
    I have the same problem with headlights. Paid the Ford dealer $100 to diagnose and give me an $700 estimate to fix. Can you or anyone point me to information on locating and removing the lighting control module? I also need to replace some instrument dash lights, replace the drivers door power window switch and the hvac air mix/blower door actuator. Dealer wants $1,600 that I don't have to fix all these. Oh, and the cd player stopped working too.
  • davelaterdavelater Posts: 2
    The latest on my issue is that I paid the dealer a nominal fee to remove the LCM. I found through a Google search, contacted them, and was told that they could rebuild/repair it for $125. I am waiting now for its return. When it's back in the car, I will post an update. Good luck with your solution to what sounds like a similar problem
  • hdave7hdave7 Posts: 9
    edited June 2010
    Thanks for the response. I hope to be able to remove the LCM myself if possible. Can the car still be driven, ie do the turn signals still function and most importantly do the brake lights work without the LCM installed?
  • njadamsnjadams Posts: 3
    My brake lights and back-up lights still worked but not the turn signals.
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