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Discussion in 'Truck & Equipment Repair' started by Baseball1, May 22, 2011.

  1. Baseball1

    Baseball1 Junior Member
    Messages: 18

    Hello, I have a 2000 f250 sd, 5.4L I have losted the left turn signal at my trailer plugin. The truck works, but not any trailers. I took it in and the genius said it was a corroded wire. I replaced the wires at the plugin, from the factory plug to the plugin, and put a new receptacle on and that wasnt it. I have followed the wire, it's the yellow one, all the way up under the hood and then i don't know from there. I've used a test light all the way. I found a frame ground at the back of the truck and redid that, cleaned it up, did nothing for my problem. Can anyone help? Thanks
    Last edited: May 22, 2011
  2. grandview

    grandview PlowSite Fanatic
    Messages: 14,609

    Hows the ground on the trailer?
  3. Baseball1

    Baseball1 Junior Member
    Messages: 18

    the trailer grounds are good. doesn't matter what trailer i hook up. I have put a test light on all the connections at the plug in and the left turn is the only one that won't work.
  4. grandview

    grandview PlowSite Fanatic
    Messages: 14,609

    What does a test light do when you put it on the prongs?

    Sorry, re read your post ,what does the the test light do when you check the wires just before they go into the plug?

    One like this?
    Last edited: May 23, 2011
  5. sno commander

    sno commander PlowSite.com Addict
    from ct
    Messages: 1,063

    if the blinker works on the truck its goota be a bad wire from where the trailer plug connector taps into the wiring harness to the trailer plug.
  6. Baseball1

    Baseball1 Junior Member
    Messages: 18

    Yes it is that same type plug as in the pic. the test light will glow on every wire, not the ground, that i test. From the plug to the wires coming into the factory connector. All except the left turn.
    Sno commander, I will continue to try the wires in and out of all the harnesses
    Thanks, I'll continue to try things and keep checking this and responding
  7. GL&M

    GL&M Senior Member
    from PA
    Messages: 223

    Don't know if your 2000 is the same as my 1999 F450 or not. The 450 has a fuse box under the hood that houses the fuses for the trailer wiring. Check the turn signal fuses there if you have them.
  8. BlizzardBeater

    BlizzardBeater Senior Member
    from Maine
    Messages: 420

    Start at the beginning using a test light or a volt meter. Where you lose 12V of pulsing power is where your problem is. Also, i'm still a little confused, did you check for power at the truck side socket? I know it sounds stupid, but check the bulb and bulb socket. A buddy brought a boat trailer to me last year said he rewired everything on the truck and trailer and couldnt get the left side to work. I cleaned and closed the socket up, took me five minutes and it was fixed.
  9. basher

    basher PlowSite Fanatic
    from 19707
    Messages: 8,993

    Before you go though all that, check the fuses. Tow systems have their own fuses.
  10. the new boss 92

    the new boss 92 2000 Club Member
    Messages: 2,989

    also if you have a 7 rv blade style pulg, stick a 4 flat adaptor in there and see it the test light will glow. if not check fuses, should be under the hood driver side. after that i would make sure the cenection at the plug is good, inside the plug aswell. your you die elc grease in the plug to keep corrosion down. good luck hope you find in elc is a pita to trace sometimes!
  11. Baseball1

    Baseball1 Junior Member
    Messages: 18

    Thanks a bunch guys! sorry, my computer was down for a few days. It was the mini fuse under the hood. I must of overlooked it in the beginning. I didn't realize there was a fuse for left and right. everything works great now. Thanks for all the input! Hope you all had a good holiday.