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Trailer wiring...again.

Discussion in 'Boats and Motors' started by Fishpro, Jul 21, 2007.

  1. Fishpro

    Fishpro Northcoast Madman

    O.K., I've checked my wiring harnesses, everything is hooked up as far as I can tell, cleaned the ground on the trailer, and I still don't have running lights. I replaced the bulbs and I checked the fuses in my truck and they seem to be in order too. I'm at a loss here.:(
  2. misfit

    misfit MOD SQUAD

    just out of curiosity,what type of vehicle do you have?make/model etc?

  3. Fishpro

    Fishpro Northcoast Madman

    '98 Chevy Blazer 4X4.
  4. misfit

    misfit MOD SQUAD

    i don't know how it's fused,but some later model trucks have a seperate fuse for trailer lights,that isn't in the regular fuse box.yours probably doesn't,but the manual will say.
    some also have wiring inside interior panels in the rear,that could also be a possible problem.problem could be on vehicle side of harness if there is good ground everywhere.only thing to do is test the hot lead to tailights to eliminate the possibility of a problem there.
  5. Fishpro

    Fishpro Northcoast Madman

    Mine has 2 fuse boxes and there isn't a fuse for trailer running lights in either of them. Theres fuses for the brakes and turn signals, but not running lights. I'll prolly have to take it to someone who knows what they are doing here in my area.:D
  6. freyedknot

    freyedknot useless poster

  7. Fishpro

    Fishpro Northcoast Madman

    Hey Van, I went and traced the wires, and they all look connected, I'll try and put a tester on them tomorrow.:confused:
  8. I ran into the same problem with my father in laws truck this year. Even checking power at the truck plug showed everything was good. Finally I pulled a taillight out and ran a new wire to the plug. Turns out the wire going to the plug had corrosion in it and was good until you tried to pull power through it. Then it would lose current.

    Cut the wire about 6 - 8 inches from the plug on the truck and splice a longer wire on it and run it up to where you know the wire is good. The closer you get to the taillight, the better chance of good wire. If it works, splice the wire in permanent and you will be good to go! Hope this helps!!
  9. Is your setup using the trailer itself to carry the ground? Many trailers do simply ground to the tongue of the trailer and the ground will be sufficient "most" of the time. However I had headaches with my trailer until I discovered that the ground was not traveling well from the light to the tongue. I had recently purchased the boat and trailer and the trailer had been painted not long before. I think that the trailer was taken apart at the "Y" section to paint and that the paint was shielding and inhibiting the connectivity. So what I did was run separate wires back to each light box and connect them in the front to the same post that the ground had been on. This ensured a good ground and I have really had no issues again since and it has been a few years. So I would suggest as a way to test it to run the separate wire outside of the trailer frame straight back to the light and see if that produces any different results. If so then simply route the wire in the same manner that the rest of the wires travel.
  10. Lewzer

    Lewzer Powderfinger

    How do you have your trailer socket hooked your your truck's wiring harness. Did you splice it or do you have the plug that plugs into your harness?
    If you spliced it into your truck's harness, check the splice for corrosion.