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Thread: Keyless Entry and Lighting Issues

  1. #1
    Carthago delenda est Lutrova's Avatar
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    Default Keyless Entry and Lighting Issues

    I have an 87 Signature Town Car that has its fair share of electrical issues. The digital fuel gauge jumps all over the place. The message center occasionally dims. Cruise sometimes resumes when using the turn signal or flashing high beams. I had hoped doing the 3g alternator upgrade might fix some of these problems, but one month later they persist. Two issues that I'm currently interested in pursuing are as follows:

    1) The keyless entry keypad is mostly working except for the trunk release and drivers door unlock. When entering the five digit code nothing happens until I hit 3/4 and all doors unlock, including the drivers door. But entering the code alone won't just unlock the drivers door. (This initially had me thinking I had the wrong code when I bought the car. I ended up making a list of every possible code and entering them with my brother - to no avail. It was only a week later when I thought to try unlocking all doors that I discovered the code printed on the module behind the glove box was correct all along.)

    Similarly, entering the code and hitting 5/6 won't pop the trunk. The soft-close motor is broken and has been unplugged, but the button in the glove box will still release the lid.

    All five keypad buttons light up when pressed and can be used for entering codes. And both the drivers lock and trunk release work through other means, so I feel like I should be able to rule out component failure at both ends. But never having done electrical work before, I'm not sure where to begin troubleshooting this.

    2) Both opera lights and the rear reading lamps occasionally get very dim. I haven't nailed down anything that might cause it to dim or bring it back. I just occasionally notice the opera lamps not lit when looking in the mirror or see the reading lamps just barely on when getting in or out. The problem seems to happen whether the car is off or on. I did replace all four bulbs with LEDs some time ago, though I didn't have the car long enough at that point to say whether the problem preceded that project or not. I've also replaced most other bulbs with the same LEDs and haven't noticed an issue on any other circuit.

    From searching through other threads it seems that some interior lights ground through screws or bolts which can come loose over time. But between these four bulbs, the opera lights must ground directly into the body and the brackets holding the reading lamps are fastened back onto the vinyl/plastic interior panel. Is there another ground somewhere that could've come loose?

  2. #2
    I'm an air-conditioned gypsy gadget73's Avatar
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    Inside the keyless entry module are some small relays. One is for trunk, one is for driver's door, one is for the rest of the doors, and the last is to kick the interior lamps on when you use the keypad. Pretty fair bet one or more are crusty. I've pulled those modules apart and carefully polished the contacts on tbe relays with strips of paper before.

    Pull the keyless module. Once out, you should see plastic tabs holding the case together. Pop those and slide the card out of the box. You'll find the relays inside. Put a sheet of paper between the lower contact and the moving finger, very gently push down on the moving finger and pull the paper out. Do that until it stops leaving black streaks on the paper. Re-assemble the module and see if that takes care of the problem.


    random dim in the rear lights sounds like a flaky power feed. Pretty sure they do not share a ground being so far apart. I don't have my EVTM handy so I'm not sure where the feed to those is exactly. The reading lamps and opera lights aren't on the same power feed though, so it must be some connector that both pass through thats gotten funky. Fair guess its someplace in the driver's side kick panel area but that doesn't narrow it down much.

    86 Lincoln Town Car (Galactica).
    5.0 HO, CompCams XE258,Scorpion 1.72 roller rockers, 3.55 K code rear, tow package, BHPerformance ported E7 heads, Tmoss Explorer intake, 65mm throttle body, Hedman 1 5/8" headers, 2.5" dual exhaust, ASP underdrive pulley

    91 Lincoln Mark VII LSC SE, triple black (Timewarp) - poly front bushings, KYB struts and shocks, Holley SystemMax1 lower intake, SilverFox AOD valve body,

    1984 Lincoln Continental TurboDiesel - rolls coal

    Quote Originally Posted by phayzer5 View Post
    I drive a Lincoln. I can't be bothered to shift like the peasants and rabble rousers

  3. #3
    Carthago delenda est Lutrova's Avatar
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    Thanks, Gadget. I'll pull the module tonight and see how gingerly I can be pulling it apart.

    I looked through my EVTM. (I own a copy, but reading these diagrams is like deciphering Chinese to me. Just like architectural electrical drawings.) It appears those fours lights do share the same ground, which is on the left side of the trunk. So I think I'll start by checking that and seeing where I end up.
    Attached Thumbnails Attached Thumbnails EVTM 10 - Reading Lights Ground.jpg  
    1987 Lincoln Town Car - Signature, "Prudence"

  4. #4
    Carthago delenda est Lutrova's Avatar
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    A quick look in the trunk revealed a very loose ground connection right above the wheel well. So I'm willing to declare victory on the lights until proven otherwise.

    I'm having a little trouble removing the keyless module. It seems almost impossible to get at one of the two screws holding it to the bracket, but now that I'm back in the house and reviewing the shop manual it seems that bracket should rotate down to give access to both screws. It's a real pain though they're both facing toward the firewall. I'll give it another shot in the morning - maybe a little daylight will help the situation.

    If the half of a sticker saying "... NOT ... SEAL" is any indication, I won't be the first person to open this module.
    1987 Lincoln Town Car - Signature, "Prudence"

  5. #5
    I'm an air-conditioned gypsy gadget73's Avatar
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    huh, wouldn't have figured a common ground but the book tells the story.

    and yeah getting that module out is kind of a PITA.

    86 Lincoln Town Car (Galactica).
    5.0 HO, CompCams XE258,Scorpion 1.72 roller rockers, 3.55 K code rear, tow package, BHPerformance ported E7 heads, Tmoss Explorer intake, 65mm throttle body, Hedman 1 5/8" headers, 2.5" dual exhaust, ASP underdrive pulley

    91 Lincoln Mark VII LSC SE, triple black (Timewarp) - poly front bushings, KYB struts and shocks, Holley SystemMax1 lower intake, SilverFox AOD valve body,

    1984 Lincoln Continental TurboDiesel - rolls coal

    Quote Originally Posted by phayzer5 View Post
    I drive a Lincoln. I can't be bothered to shift like the peasants and rabble rousers

  6. #6
    Carthago delenda est Lutrova's Avatar
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    Turns out getting at those screws was a non-issue when the bracket just unhooked from the panel after a little monkeying around. It's amazing how rusty the bracket is for something tucked away under the glove box. I assume that's from condensation in the cabin over the last 30 years.

    The two cards, unfortunately, are pretty firmly fixed to the inside of the case. I don't see any screws inside so I'm guessing they've somehow corroded to the plastic. There's certainly a good amount of corrosion on the contacts for the wires. I'd try strongarming them out, but I can see a ribbon cable and two plastic supports, so it looks like they both slide out at the same time or something breaks.

    The four copper coils are, I'm assuming, the relays? Is it possible to get at what I need to clean with them still in the case?
    Attached Thumbnails Attached Thumbnails 200402 Electronics 3.jpg   200402 Electronics 2.jpg   200402 Electronics 1.jpg  
    1987 Lincoln Town Car - Signature, "Prudence"

  7. #7
    I'm an air-conditioned gypsy gadget73's Avatar
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    hm, I don't remember having much issue getting the card out once the end cap was off. Pretty sure there are no screws or glue or any of that. Maybe needs a jiggle or something to persuade it? Been a number of years since I was into one of those modules so I might be forgetting some retainer tab or whatever. I don't remember having any special trouble with it so if there is another thing holding it together it should be fairly easy to find. What I'm remembering of that keyless box was a single board, not a stacked board like that though. Last one I did out of a Towncar was an 86, and not mine. Entirely possible I'm just working with faulty memory here. If that has the keyless entry code on it and your power locks do not work without it plugged in, thats the magic box.

    yeah the copper things are the relays. If you can get in there to clean the contacts that will do it. Just don't push down on them hard, the contacts aren't real stout. It wants just enough pressure to make the paper drag across the contacts.

    86 Lincoln Town Car (Galactica).
    5.0 HO, CompCams XE258,Scorpion 1.72 roller rockers, 3.55 K code rear, tow package, BHPerformance ported E7 heads, Tmoss Explorer intake, 65mm throttle body, Hedman 1 5/8" headers, 2.5" dual exhaust, ASP underdrive pulley

    91 Lincoln Mark VII LSC SE, triple black (Timewarp) - poly front bushings, KYB struts and shocks, Holley SystemMax1 lower intake, SilverFox AOD valve body,

    1984 Lincoln Continental TurboDiesel - rolls coal

    Quote Originally Posted by phayzer5 View Post
    I drive a Lincoln. I can't be bothered to shift like the peasants and rabble rousers

  8. #8
    Carthago delenda est Lutrova's Avatar
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    Well I gave it the old college try, but there was no budging those cards. So I did the next best thing and took my Jap saw to the case. It wasn't the cleanest operation but it got the job done. I managed to clean the contacts on 4 out of 5 relays, though none really had any buildup. After sitting on my desk for several weeks I finally sealed the case back up and threw it into the car.

    ...And there was no change. So either the issue is somewhere else, either in the module or wires, or I didn't clean it properly. Either way, it looks like these modules run about 30 bucks on eBay, so next time I'm bothered by it I might just try swapping it out for another.

    Switching gears, is the light for the driver's mirror thermometer serviceable? I thought I'd read somewhere that it's illuminated by a fiber optic cable running back to somewhere in the interior. But elsewhere it appears there might be an LED inside the unit.
    Attached Thumbnails Attached Thumbnails 200427 Module Sealed.jpg  
    1987 Lincoln Town Car - Signature, "Prudence"

  9. #9
    Beater gonna beat sly's Avatar
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    If I remember correctly... The light source is inside of it. The only lines coming out of those are the electrical connectors for the power movement, heated (if equipped) and light for the thermometer.
    If I don't remember correctly, I'm thinking of the early 80s version and the later version is different (I don't think it is).

    Only two things are infinite, the universe and human stupidity, and I'm not sure about the former. -- Albert Einstein
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  10. #10
    Carthago delenda est Lutrova's Avatar
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    If it's internal to the thermometer then it sounds like there's no replacing it. That seems like an oversight on someone's part. C'est la vie.

    One thing I noticed today after reinstalling the keyless module is my Alarm light now flashes when I get in. I've owned the car for close to a year now and I didn't realize it had an alarm. Looking through the EVTM it doesn't appear the keyless module really interacts with the anti-theft, so I'm guessing there was a loose ground that I reconnected under the glove box when putting things back together.

    I don't really know how useful the anti-theft on these cars is, but I suppose accidentally fixing it might be a silver lining to this whole effort.
    1987 Lincoln Town Car - Signature, "Prudence"

  11. #11
    Beater gonna beat sly's Avatar
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    It may also just be mounted at the back end and accessible from the hole to the door. Would have to take it off to find out. It's been at least 7 years since I've seen one now, having sold the car I had with one.

    Only two things are infinite, the universe and human stupidity, and I'm not sure about the former. -- Albert Einstein
    rides: 93 Crown Vic LX (The Red Velvet Cake), 2000 Crown Vic base model (Sandy), 2003 Expedition (the vacation beast)
    Quote Originally Posted by gadget73
    ... and it should all work like magic and unicorns and stuff.
    Quote Originally Posted by dmccaig
    Overhead, some poor bastards are flying in airplanes.

  12. #12
    I'm an air-conditioned gypsy gadget73's Avatar
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    never had one of those lights quit, so never had cause to figure out how to replace it. The thermometers don't typically come out nicely so I would advise not messing with it.

    86 Lincoln Town Car (Galactica).
    5.0 HO, CompCams XE258,Scorpion 1.72 roller rockers, 3.55 K code rear, tow package, BHPerformance ported E7 heads, Tmoss Explorer intake, 65mm throttle body, Hedman 1 5/8" headers, 2.5" dual exhaust, ASP underdrive pulley

    91 Lincoln Mark VII LSC SE, triple black (Timewarp) - poly front bushings, KYB struts and shocks, Holley SystemMax1 lower intake, SilverFox AOD valve body,

    1984 Lincoln Continental TurboDiesel - rolls coal

    Quote Originally Posted by phayzer5 View Post
    I drive a Lincoln. I can't be bothered to shift like the peasants and rabble rousers

  13. #13
    fomoco panthers !
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    I had one of those lights go out. Easier to replace the whole mirror assembly especially with an older car, where parts have stuck in place.

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