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Wiring - Lot's of sparks! YEAH!

Discussion in 'The Hokey Ass Message Board' started by invizibletouch, Mar 20, 2009.

  1. invizibletouch
    Joined: Jan 17, 2008
    Posts: 302

    invizibletouch
    Member
    from Mobile, AL

    Following FatHack's wiring tech and ran into a situation that probably has happened to many...

    Wiring my headlamps. No existing wire other than some short strands from the headlamps that were in the car when I got it (basket-case). It's a 49' Ford.

    1. Spliced in new wires from about 6 inches in from the headlamp socket
    2. Individual ground from each headlamp to the body
    3. Battery - NEG terminal grounded to the block

    When I clamped a headlamp wire from the lamp to the + terminal on the battery I got nice bright headlamps!

    Then the shit sparked, frizzled, and melted my wire. :mad:

    6 volt bulbs with a 12 V battery? How the hell do I even tell whether its a 6V or 12V bulb?

    Thanks!
     
  2. duste01
    Joined: Nov 5, 2006
    Posts: 1,213

    duste01
    Member

    back of the bulb, it says in black ink next to the electrical blades along with the part number

    you miight want to check to see if it has been converted to 12v. count the water vents on th ebattery. 3= 6v 6= 12v each cell is 2volts.

    If its still original and its 6v, and the ground cable shoould be on the positive post. If it has been converted, you may just have an isssue with the bulb.
     
    Last edited: Mar 20, 2009
  3. manyolcars
    Joined: Mar 30, 2001
    Posts: 8,226

    manyolcars

    16 years ago when I got my 39 Ford, ALL the wires were red and made a huge rats nest under the dash.
    I could shake the mess of wires and get a nice shower of sparks.
     
  4. Micky D
    Joined: Mar 20, 2009
    Posts: 8

    Micky D
    Member
    from Olympia,WA

    Count your blessings. I bought my 1955 Belvedere last year and the old 6v wiring and newer 12v wiring all in the car. What a rats nest under the dash. I pulled out everything 2 months ago and put in a new wiring harness. I had to have a friend help me with this mess as even though all the new wires are marked its still not an easy task.
     
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  5. duste01
    Joined: Nov 5, 2006
    Posts: 1,213

    duste01
    Member

    not to mention dryrotted cloth insulation causing bare wire shorts
     
  6. Johnny1290
    Joined: Apr 20, 2006
    Posts: 2,834

    Johnny1290
    Member

    uh....why exactly did you do this in the first place?!?

    just replace all of it...all your bulbs, sockets, wiring, ignition switch, headlight switch, the whole 9 yards...use a american autowire kit, everything is included...well switch wise anyway I don't think they'll have speedometer cluster bulbs
     
  7. invizibletouch
    Joined: Jan 17, 2008
    Posts: 302

    invizibletouch
    Member
    from Mobile, AL

    Hey Johnny that's the whole point, I AM replacing all of it. Actually there isn't anything in the car. This is step one for me. Starting with the headlamps and working toward the inside of the car.

    Just pulled a bulb and it appears to rate 6-8V so I guess that answers my original question. 12V ona 6V bulb = lotsa sparks. :D
     
  8. retromotors
    Joined: Dec 10, 2008
    Posts: 1,045

    retromotors
    Member

    Ummmm .... 12 volts to a 6 volt bulb should blow the bulb, but not melt any wiring!
    Methinks you have another problem goin' on.
    Possibly review one of the posts above regarding battery polarity?
    Good luck!
     
  9. Something to be aware of---There are 3 prong on the back of a headlight bulb. Now, logic would dictate that the center prong is ground, and the other two are ---one for high beam and one for low beam.---BUT--It ain't that way!!! When viewed from the back of the bulb. with the odd prong on "top", the right hand prong is high beam, the left hand prong is ground and the other prong (the one on "top" is the low beam. This has fooled me in the past.---Brian
     
  10. Fat Hack
    Joined: Nov 30, 2002
    Posts: 7,709

    Fat Hack
    Member
    from Detroit

    The melted wire has me a little curious...but you say the lights lit real bright for a second or so? That jives with 6v bulbs on a 12v battery...bright lights followed by POOF! The melted wire makes me think that one or both of the bulbs may have shorted out when they (or it) blew...creating a dead short that would melt a wire in short order!

    I never like to re-use the original sockets for headlights...new ones only cost about four bucks each and they come with 16 or 14 gage wire usually.

    Looked for anyplace the wires may have crossed or shorted, too.

    Oh yeah, one other thing I should mention, I don't mind testing smaller bulbs by touching wires to the battery posts, but headlamps draw more amperage, so you'll get a pretty hot spark when you touch the wires...and hot sparks near automotive batteries can be bad news! If I'm going to test the headlamps before they're wired in to the interior, I use a switch (with at least a 20 amp rating) and an inline fuse holder with a 20 amp fuse in my testing procedures. That way, there's no sparks when you attach the wires to the battery (with the switch off), and if there's a problem once the switch is thrown, the fuse will pop.

    (Ha Ha...trust me, once you explode a 12v car battery, you'll be cautious around them for the rest of your life!!!) :eek:;):cool:
     
  11. invizibletouch
    Joined: Jan 17, 2008
    Posts: 302

    invizibletouch
    Member
    from Mobile, AL

    Thanks man! Gave the wiring a rest today...probably a good decision! lol Had a buddy come fab up a new crossmember so that kept me busy.

    Gonna follow the advise given and give it shot tomorrow hopefully! Thanks guys!
     
  12. invizibletouch
    Joined: Jan 17, 2008
    Posts: 302

    invizibletouch
    Member
    from Mobile, AL

    Right on! Thanks man, I'm gonna take a look at that.
     

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