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Why do I keep blowing the brake light fuse?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by 90K5, Mar 6, 2001.

  1. 90K5

    90K5 1/2 ton status

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    I have a 5x8 trailer that I tow sometimes. Every time I do, I blow the fuse for the brake lights. I started by rewiring the trailer...twice. Then I looked under my truck and saw a mess of wires. The factory harness was still wrapped in tape near the tailpan. The harness that went to the trailer was spliced into it. I bought a new harness thta plugs in between the harnesses for the lights and took the old factory one out. Now the wiring is all cleaned up, and it is still blowing fuses. The grounds are connected on the truck and trailer side, and there are no splits i nthe wires thta I see. I had it in park and pushed the brake down several times and it didn't blow, but once I started moving, I soon noticed that the brake warning light was on again. I'm getting really mad at this...anyone have some ideas?

    90K5

    See my truck at <A target="_blank" HREF=http://albums.photopoint.com/j/Albumindex?u=1329584&a=9886502>http://albums.photopoint.com/j/Albumindex?u=1329584&a=9886502</A>
     
  2. dyeager535

    dyeager535 1 ton status Premium Member

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    I had a similar problem. Wired up a very small trailer. Two lights, thats IT. Hooked the wiring on the truck up. (mine too, was a jumble of existing wire) I spent the time with the multimeter, making sure each wire did what it was supposed to do regarding the turn signals, brake lights, etc.

    Hook the trailer up, drive a bit, turn on headlights, bang. Blown fuse. Same thing over and over. Left it over at my dads, so he could mess with it if he wanted (retired) I come home, see him standing next to it. Asked him if he fixed it. Yes he did. How? Cut the wire I used as a ground on the truck side of the plug. All I can guess is that one wire, when the lights were on or whatever, was somehow hooked to a ground. The trailer grounds fine through the ball in my case, the lights on the trailer are grounded to the trailer frame. Just something to try I guess...

    Dorian
    My K5 and Chev/Olds tech/links page: <A target="_blank" HREF=http://www.dorianyeager.com/index2.html>http://www.dorianyeager.com/index2.html</A>
     
  3. jimmyjack

    jimmyjack 1/2 ton status

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    It has to be a ground fault somewhere. Maybe a wire coming from the brake switch ? Maybe its the brake switch.

    creepin' and crawlin'

    Jim
     
  4. UseYourBlinker

    UseYourBlinker 1 ton status

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    Because you have a short somewhere. Check every wire going to the trailer, and coming back from the trailer.

    <font color=blue> I'm down with the clown, till I'm dead in the ground.</font color=blue>
     
  5. 90K5

    90K5 1/2 ton status

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    It turned out being the actual light on the trailer. For some reason it wasn't working. I tried switching it out with another one I had lying around and it worked.[​IMG]

    90K5

    See my truck at <A target="_blank" HREF=http://albums.photopoint.com/j/Albumindex?u=1329584&a=9886502>http://albums.photopoint.com/j/Albumindex?u=1329584&a=9886502</A>
     
  6. coopertwpk

    coopertwpk 1/2 ton status

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    On some trucks the white wire is a back up light others its the ground I dont know why but check it out

    88k5 silverado w4"lift soon to have <font color=orange>d44 and corp14ff</font color=orange> with 4.56s
     

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