Headlights work…sometimes

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This topic contains 8 replies, has 6 voices, and was last updated by  sabreur76 4 months ago.

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  • #303584

    vdransoff
    Participant

    @vdransoff

    Hey Guys!

    This is my first post – so be gentle.  I just bought my first MG TD fiberfab kit car with a ’71 vw engine.  No sooner do I get it home, the headlights won’t come on.  I started it up a day later, they came on and then went out.

    I assume there is a short or loose connection somewhere.  Where should I begin to look.  The car is going to be inspected tomorrow in PA and I am a bit freaked out that I won’t be able to fix this before then.

    Any help is appreciated.

    Victoria

    • This topic was modified 4 months ago by  pmossberg.
    #303585

    kall
    Participant

    @kall

    Sorry you are “short” of time to repair your “disconnect”.

    Troubleshooting thoughts:

    1. Goes on and off – can’t be a fuse, they only work once.

    2. Both headlights? – can’t be the bulb.

    3.  Both high and low beams – not the “dipper” switch on the floor.

    4. Does your car have the headlight “high/low” switch as part of the turn signal switch? – a complex circuit involving tiny switch contacts in the steering wheel hub and a relay somewhere and the wiring in between.  Find the relay and work in both directions from there.

    5. Bad headlight switch on dash? – a very common problem, even if the parking lights work OK.

    6. Loose or corroded wire connections, especially the crimp-ons? – wiggle, shake, and tug one connection at a time.

    7. Need a diagram? There is probably one in the site library or Google 1971 vw bug wiring diagram and several will pop up.  Caution – these diagrams probably will not match your car exactly, especially the color codes.  Still, they are helpful.

    The good news, troubleshooting the electrical system yourself will benefit you in the long run the next time you have an electrical problem.

    😣😳😡😃🍺

     

    #303586

    toller
    Participant

    @toller

    To add to Kall’s diagnostics a common problem that can be intermittent in nature is a bad ground. You can test with a Volt/ohm meter or a 12volt light bulb with alligator clips as per John Muir’s diagram. Before offering more advice are you going to do the diagnostics and repairs yourself or go to a mechanic?

    David B Dixon
    Port Perry ON CA
    Sabine

    #303587

    toller
    Participant

    @toller

    My fiberfab does not use a VW wiring harness. The factory used single colour wires with numbered tags on my TDR that after 35 years have dried and fallen off some of the wires. There is a Fiberfab wiring diagram in the tech manual section of the website

    David B Dixon
    Port Perry ON CA
    Sabine

    #303588

    vdransoff
    Participant

    @vdransoff

    My plan was to try to troubleshoot this myself as I don’t have much time.  As I mentioned, the car is being inspected tomorrow.

    #303589

    newkitman
    Participant

    @newkitman

    I’d first check the ground wire. Could be loose. Pull the headlight and check the headlight connector. The ground wire (if VW color coding is used will be BROWN.) If not VW wiring it’ll be black and probably will NOT run all the way to the dash. Most likely it’ll run to the chassis somewhere near the headlight area. My TD is a Fiberfab and is wired that way.

    Allen Caron
    VW based 53MGTD - "MoneyPenny"
    "If one thing matters, everything matters" - from the book The Shack

    #303590

    toller
    Participant

    @toller

    Victoria
    What Allen means by checking the ground wire on the headlight connector is to verify connectivity between the negative post on the battery and the ground wire on the connector. To check continuity I use a volt/ohm meter. If you do not get a confirmation of connectivity you can try to trace the wire from the connector back to some place on the chassis. Alternatively you can run a new wire from the known good ground to the connector. You can check continuity with the John Muir test light using the positive battery post by touching the contact on the bottom of the light to the post and running a wire from the negative wire on the headlight connector to the casing on the lightbulb. If the light comes on the ground wire to connector is good. As mentioned by Kall give the ground wire on the connector a pull and if the light goes off you have found the source of the problem. Alternatively you can forego the testing and just run a new ground wire from the chassis to the connector. You may find two ground wires going to the connector. One is from the chassis and the other will go to the connector on the other headlight. Let’s us know what you find

    David B Dixon
    Port Perry ON CA
    Sabine

    #303591

    billnparts
    Participant

    @billnparts

    Check the grounds. Always first step in a non metal car.

    You’re in Malvern. Carlisle is 1-1/2 hours away. There is a small army of kit car owners here more than willing to assist. The hotel parking lot sometimes resemble a race car paddock. Remember to attend in the future.

    Good luck with inspection.

    Bill Ascheman
    Fiberfab Ford
    Modified 2.3, 5sp., 4:11
    Autocross & Hillclimb
    "Drive Happy"

    #303592

    sabreur76
    Keymaster

    @sabreur76

    I had the exact same problem when I first got my FiberFab.  It turned out to be a bad ground.  I’m not much of a fix it myself guy so I took the car to Gene’s Foreign Car Service on West Chester Pike in Broomall.  They fixed it and they will do inspections.  If you decide to take it there, ask for Harold and tell him “Frank” with the red MG replica sent you.

    Vicenç - (bee sense)
    Pembroke Pines, FL
    1983 FiberFab MiGi II - "Montse"

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