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Headlight fuse pops when I "get on it"

Discussion in 'The Hokey Ass Message Board' started by DaddyO's..Deuce, May 19, 2013.

  1. DaddyO's..Deuce
    Joined: Jul 31, 2011
    Posts: 782

    DaddyO's..Deuce
    Member
    from Missery

    Anyone had this problem? Headlights are fine when driving "normal" but lay into it and your in the dark! Makes for an exiting ride, that's for sure. Never had a problem with this before. Just installed a new set of 34 commercial headlights from Speedway. Both are grounded to the frame and are currently wired up on high beam only. Any thoughts would be helpful, thanks.
     
  2. metal man
    Joined: Dec 4, 2005
    Posts: 2,949

    metal man
    Member

    That's a good gas saving device.....
     
  3. A Rodder
    Joined: Jul 13, 2008
    Posts: 2,477

    A Rodder
    Member

    Wow, I am looking forward to seeing the answer to this one
    I can't really wrap my head around it being a voltage / rpm type problem.
    I think you may have some wires grounding out behind the light possibly or another short that is ready to ground at any time and when you drop the hammer the wiring is moving slightly and grounding out then.
     
  4. daddio211
    Joined: Aug 26, 2008
    Posts: 5,998

    daddio211
    Member

    Finish wiring them and see if there's any difference. Not likely, but have it 100% before you start chasing ghosts.

    Popping a fuse USUALLY indicates too much draw (amperage) on the circuit. Can't see how getting on it (higher RPM therefore more potential for alternator output) would create more demand on the fuse.....

    Wait, how are they wired? Heavy duty or new headlight switch involved? That could be faulty, but I'm troubleshooting something I can't see.

    Sent from atop my toilet using the TJJ app for Android.
     

  5. GassersGarage
    Joined: Jul 1, 2007
    Posts: 4,728

    GassersGarage
    Member

    High beam only? Like Daddio said, finish wiring then trouble shoot.
     
  6. hdman6465
    Joined: Jul 5, 2009
    Posts: 652

    hdman6465
    ALLIANCE MEMBER

    CHECK THE CHARGING. Quickest and easiest thing to do.
     
  7. trace the wires out, it sounds like a wire is pinched or pulled during body roll/twist.
     
  8. harpo1313
    Joined: Jan 4, 2008
    Posts: 2,100

    harpo1313
    Member
    from wareham,ma

    does it blow in nuetral while reving it up?Why are the high beams just wired up?
     
  9. GirchyGirchy
    Joined: Mar 17, 2011
    Posts: 222

    GirchyGirchy
    Member
    from Central IN

    Did you size the fuse correctly for the high beams? They're normally higher wattage and draw more current.
     
  10. pottsie454
    Joined: Feb 12, 2011
    Posts: 399

    pottsie454
    Member

    I'm thinking the regulator sensing wire isn't seeing the correct voltage and over compensating with over voltage. As others have said hook up a volt meter and try to reproduce the problem.
     
  11. GirchyGirchy
    Joined: Mar 17, 2011
    Posts: 222

    GirchyGirchy
    Member
    from Central IN

    Higher voltage would draw less current....if the fuse is blowing, the voltage would likely be dipping down, drawing more current.
     
  12. I'd run the harness thru a wiggle test
     
  13. Ebbsspeed
    Joined: Nov 11, 2005
    Posts: 5,414

    Ebbsspeed
    ALLIANCE MEMBER

    True only if the resistance changes. While a headlight resistance does vary slightly, I'm 99.5% certain that if you bump up the voltage across a headlight filament, you will also see a rise in current.

    To the OP, it does sound like you have a wire that is moving under acceleration. Could be a headlight wire, if you have an alternator with a remote sensing lead, that lead could be losing it's connection and going open, which would result in the alternator output voltage increasing, and a corresponding current increase through the fuse. Albeit for a short time. No pun intended.
     
  14. Lobucrod
    Joined: Mar 22, 2006
    Posts: 4,122

    Lobucrod
    Alliance Vendor
    from Texas

    Could be a problem with your flux capacitor back feeding through the electrical system. Does it only happen when you hit 88 MPH?
     
    Bandit Billy likes this.
  15. I experienced a similar problem with my old 4 door Deuce,,I was running down the interstate running with traffic and suddenly no lights....

    I had blown a fuse,I road down the shoulder for about a mile and eased into a well lit gas station and got under the dash to discover a blown fuse.

    I bought a couple,installed one and flipped the headlights on.. everything worked as it should and I hit the interstate not having any problem until I pulled off the highway and meandered the dark back roads leading home,,I tapped the dimmer switch and the lights went out.

    A few days later I started looking for a short and couldn't find one,,I convinced myself it was it was the dimmer switch and replaced it,,sitting in the shop I cranked the car,turned on the lights,hit the dimmer switch both high and low beams worked flawlessly and I patted myself on the back as I had solved the problem.

    By this time daylight savings time had started and I was usually home before I need the headlights...but one evening it started raining and I flipped on the lights and every thing worked as it should then about 2 miles form my destination all of a sudden no lights!

    I didn't try to find the problem that evening but within a few days I stuck a new bigger fuse in thinking the previous one was to small,,hit the lights and everything worked as it should,,I drove the car around in the daylight with the lights for most of the day on bright and on the way home I noticed the hi beam indicator light was out.

    By now I had just about wore out my tester but upon return arrival to the shop out it came again,,this time I found my problem,,it was my headlight switch,,I removed it was shocked to see that the phenolic material on the top of this particular headlight switch had deteriorated and cracked and obviously when I hit a bump it would ground out.

    I replaced it and never had a problem again. HRP
     
  16. Engine man
    Joined: Jan 30, 2011
    Posts: 3,476

    Engine man
    Member
    from Wisconsin

    Why would you be driving at night with high beam only? If you met me at night with high beams on you can expect a rock through your windshield.

    I had a Caddy that rubbed through the loom cover and the breaker would pop when I hit a bump. It's easier to find at night as it sparks.
     
  17. A circuit breaker would be a plus in some of the scenarios offered above, many later model (60s and up..maybe earlier?) OE switches have them built-in, and CBs can be had for fuse slots as well.
     
  18. If they are aimed correctly(down and to the right), you'd never know they were high beams.
     
  19. Obviously,you don't have a car with small bulb headlights,,the early cars with a glass lens and small bulbs on high beam are marginal at best.

    They don't even begin to compere with normal seal beam lights and pale in comparison to the extra bright blue lights that are common on todays autos. HRP
     
  20. DaddyO's..Deuce
    Joined: Jul 31, 2011
    Posts: 782

    DaddyO's..Deuce
    Member
    from Missery

    Thanks for all the replies. Getting ready to head out to the garage and have a look at things. To answer a few of your questions, they are wired up on high beam only because I've never had a dimmer switch on the car. The old headlights were wired this way and I ran it for 7 years and never had a problem, also never had anyone bright light me. Also noticed that my new engine seems to have separated the rubber from the metal part of my motor mount (ain't torque great!) So my engine got quite a lean last night. So guess I'll switch over to some all metal motor mounts. She's not really built for comfort anyway. I guess I could run more wires (to try and hide) and put in some sort of dimmer switch, but it had always done fine without one up to this point without. Going to check my grounds and pull my headlight switch out to check next, updates to follow...
     
  21. Hnstray
    Joined: Aug 23, 2009
    Posts: 11,850

    Hnstray
    ALLIANCE MEMBER
    from Quincy, IL


    Uhhhh........then, functionally, that would make them LOW beams, would it not?
     
  22. need louvers ?
    Joined: Nov 20, 2008
    Posts: 12,906

    need louvers ?
    Member

    I'm going to guess that Hot Rod Primer has this one nailed! I have had a similar situation with the Plymouth at one time. With non relayed headlights on the car and running my high beams most of the time back in the sealed beam days I would find the regular Cole Hersey switches would last about two years and that was it. I have since gone to a set of Hella flat lens Hallogen headlights with high output European spec bulbs, (the human smuggling types have a bad habit of driving loaded trucks down the opposing left lane with no lights to avoid border patrol stations on highway 8!) and relays so the switch doesn't take the entire load of the headlight out put.

    Barring that I would check regulator function as everybody else said.
     
  23. A Rodder
    Joined: Jul 13, 2008
    Posts: 2,477

    A Rodder
    Member

    Ehh, just brighter low beams:D
     
  24. plym_46
    Joined: Sep 8, 2005
    Posts: 4,018

    plym_46
    Member
    from central NY

    Sounds like you have a overcharging issue. Are you running a genny or an alt. If genny, what is the condition of your Voltage regulator? Is the cut out circuit operating correctly??? Do you have an ammeter, if so what is it telling you? Or is it as simple as pinching a wire into a direct to ground short during engine movement?
     
  25. Dan Timberlake
    Joined: Apr 28, 2010
    Posts: 1,302

    Dan Timberlake
    Member

    I think if there is a fully charged battery in the system it would be able to supply MANY amps ( a couple of hundred) with minimal voltage drop ( 1 or 2, or maybe 10.5-ish) for several seconds, just like it has to starting my car on a frosty morning. Look what a pair of batteries can do @ 4:00 here -
    http://www.youtube.com/watch?feature=endscreen&NR=1&v=PV5oLPLUzrM

    DC test - Hook a 6 volt incandescent stop light bulb to the terminals of a 6 volt battery with an ammeter in the line, and a volt meter across the bat terminals. Read and record amps and volts. Then repeat with a 12 v battery. Quickly read and record amps and volts.

    AC test - Rewire a 120 volt test receptacle adapter as 240 volts. Set up video camera. Borrow your neighbor's pride and joy expensive 120 volt shop vac, and Plug in to 240 volts. Post video on You-tube.
     
  26. mustang6147
    Joined: Feb 26, 2010
    Posts: 1,847

    mustang6147
    Member
    from Kent, Ohio

    I am leaning toward 2 possibilities...

    HRP thing..... and perhaps at higher speeds, or when you hammer it, the engine leans, or fan blows just enough causing a wire to ground, thus popping the fuse...

    I would even check wires near the throttle linkage under the dash
     
  27. DaddyO's..Deuce
    Joined: Jul 31, 2011
    Posts: 782

    DaddyO's..Deuce
    Member
    from Missery

    [​IMG]
    The headlights in question
    [​IMG]
    The plot thickens, here is the headlight switch which has a 30amp fuse which has NOT blown, the fuse in the fusebox (which calls for a 20amp) is the fuse that has blown, even tried a 25 with the same result. However it's only the headlights that are affected, taillight does fine. I switched headlights/taillight/and engine over the winter. The fusebox came out of a 76 Pontiac if I remember correctly. I am running an alternator also. [​IMG] alternator is just a standard GM, not a one wire unit.
     
  28. DaddyO's..Deuce
    Joined: Jul 31, 2011
    Posts: 782

    DaddyO's..Deuce
    Member
    from Missery

    Also installed a battery quick disconnect this winter, but don't see how this would affect anything. [​IMG]
     
  29. pottsie454
    Joined: Feb 12, 2011
    Posts: 399

    pottsie454
    Member

    Forgive me if I'm wrong, I'm no electrician, but I did stay in a holiday inn last night... I don't know if my thought process is correct but hear me out.. More voltage causes a light to be brighter, reason being is the filament is being stretched causing more resistance, more heat, equals more current/amps. Am I wrong? I always like to learn something new....
     
  30. DaddyO's..Deuce
    Joined: Jul 31, 2011
    Posts: 782

    DaddyO's..Deuce
    Member
    from Missery

    So I dug out the old headlights and they only had one wire coming out. If this is the hot wire how are these grounded? [​IMG] the new headlights have 3 wires, one ground, one high beam one low beam. I wired the old "hot" wire to the green high beam wire and ran the ground wire to the frame.
     

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