Driving lights blow fuse

Discussion in 'Electrical' started by Big Papa Jerry, Oct 16, 2008.

  1. Big Papa Jerry

    Big Papa Jerry Member

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    When I turn on driving lights they blow my headlight fuse after 2-5 minutes. Buddie of mine said the wire going into turn/driving light pulled out ... checked wires going into both sides, they visually look good. Put back together and same thing. Was wondering if anyone had this problem?? and any suggestions on what the problem could be -or- how to find the problem??
     
  2. glider

    glider Veteran Member

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    I would suspect the wire going into the housing if it has some history of pulling out. You can disconnect the plug at the end of the wire in the fairing and see if it clears the problem indicating that the problem is in the light and not the bike harness.
     
  3. Big Papa Jerry

    Big Papa Jerry Member

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    Thanks Glider, I unplugged the lights and took them out. started bike and turned on switch...let run for 20 minutes and everything stayed on. Could it be the sealed lights? and maybe the positive hooked up backwards? The lights have the same spade plug on both sides along with a screw. There is no indication on what side is pos or neg. Any suggestions or link so I can see whats what?
     
  4. NEWHD74FAN

    NEWHD74FAN Experienced Member Retired Moderators

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    Use a Digital Multi-Meter DMM and self powered OHMS setting (with no power connection to the lights), and measure each spade lug with respect to bike chassis. You can determine if one of the two spade leads is grounded to chassis; then check your service manual wiring diagram for running lights option and verify color code and plug wiring harness, relay wiring and polarity matchup. Since the fuse does not blow immediately, you are probably exceeding the current rating of your headlamp fuse, or have sneak leakage current due to improper/pinched wiring, and may have to run a separate circuit, fuse, switch/relay for your driving lights (which were probably just wired in parallel for speed, simplicity or laziness if a new installation). Glider has a wiring diagram in his Maintenance Lighting thread... :57:

    You should check how much current your driving lights are drawing. Your fuse rating for your headlamps may be exceeded...expecially if you bumped up your standard headlight power 55/60W to brighter aftermarket one 65/70W as an example with the burden of the accessory lighting exceeding the standard 15A fuse. P (Watts) = I (Amps) x E (Volts) :coffee
     
  5. Big Papa Jerry

    Big Papa Jerry Member

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    First thanks for info. I know what wire is what so no need to test for current. The lights are still stock equipment from Harley (no upgrades on lights yet).I guess you didn't understand the question. The lights are disconnected sitting on my work bench, ultra classics came with them already wired and installed from Harley.

    So the question is can the lights be bad as to cause a short?? Also, the spade connectors on the lights which 1 would I hook up the Grey with black stripe wire to ??
     
  6. Big Papa Jerry

    Big Papa Jerry Member

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  7. silentflyer

    silentflyer Active Member

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    Find an amp meter, put in series with the + line and check the current going to the lamps, may be just the fuse current rating is very close to the actual ammount being drawn by the lamps. May want to try a "slo-blow" or time delay fuse, or better yet a circuit breaker.
     
  8. Big Papa Jerry

    Big Papa Jerry Member

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  9. glider

    glider Veteran Member

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    If you mean that you unplugged the bulbs themselves and the problem went away, it could be that you moved the offending wire in the housing where it enters the shaft of the mount for the light, or they may be oversize bulbs or improper fuse in the circuit. It should be a 15 amp in there.
     
  10. Big Papa Jerry

    Big Papa Jerry Member

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    Okay....have lights completely out, put everything back together...ran bike with headlight and driving light switch on. everything good as far as wiring. going to get new bulbs and hope that's the problem. :dknow They are the original 01 bulbs, so I'll try new ones (would probably need to replace them soon anyway).