Wiring help
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Freshman User
Joined: May 2013
Posts: 32
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From: Northern KY
Wiring help
Recently purchased a 1986 f250 460. I've had the unfortunate experience of finding a rats nest of wiring the PO has made under the dash. The real problem here is that the truck can't be driven because the brake lights and turn signals don't work. Given the severity of the mess, I thought I could buy a new wiring harness and re-wire it, but LMC wants $640 for a generic harness.
I can't seem to justify that expense for a farm truck, but I also want the truck in good working order. I'm not an electronics expert but I'd welcome ideas for alternatives.
Seems that there aren't many older f250s at the local pick and pull salvage yards.
I can't seem to justify that expense for a farm truck, but I also want the truck in good working order. I'm not an electronics expert but I'd welcome ideas for alternatives.
Seems that there aren't many older f250s at the local pick and pull salvage yards.
Senior User
Joined: Nov 2007
Posts: 207
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buy a haynes manual, flip to the back, trace the wires with colored pencils that loosely represent the colors they say they are, then find them under the dash and figure out where your problem is. Might just be the turn signal flasher too, have you replaced it?
pedant
Joined: Jan 2008
Posts: 23,576
Likes: 38
From: EXTREME southwest CT
I have a similar situation right now.
My truck keeps popping the fuses (1&5) for the brakes and turn signals.
Though our wiring is different year to year, the problem might be the same one.
I am posting to subscribe this thread, and will let you know what I find.
My truck keeps popping the fuses (1&5) for the brakes and turn signals.
Though our wiring is different year to year, the problem might be the same one.
I am posting to subscribe this thread, and will let you know what I find.
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Freshman User
Joined: May 2013
Posts: 32
Likes: 0
From: Northern KY
I ordered the Haynes manual over the weekend. Should be here any day. I have power at the fuse block on all fuses. The parking lights and headlights are working. I saw the hazardsashing briefly when I was messing with that switch, but now it's not working. This leads me to believe the relays are fine. So there must be a bad connection in the steering column or under the dash. The PO changed the column because the tilt wheel broke.
Guess I just need a whole lot of time an a tester.
Guess I just need a whole lot of time an a tester.
Postmaster
Joined: Feb 2011
Posts: 3,560
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the brake lights, turn signals, and hazard lights all run through the turn signal switch, and i've heard of that switch failing and knocking out all of them. thats where i would start looking.
jim, seeing that you're popping both fuses, i would suspect you have a problem somewhere further back, likely a short to ground in the trailer light wiring. but follow the whole harness and look for and damage.
jim, seeing that you're popping both fuses, i would suspect you have a problem somewhere further back, likely a short to ground in the trailer light wiring. but follow the whole harness and look for and damage.
Moderator
Joined: Jan 2001
Posts: 56,951
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From: Virginia
Since you messed with the hazard switch and something happened, take the hazard switch and work it up and down rapidly 6 or 7 times and see what happens.
And also don't forget, these trucks are famous for the keyswitch not returning to the proper position after the engine is started. After you start the engine, lightly wiggle the key back and forth and see what happens. This will usually affect the wipers and the guages, but can also affect other circuits.
And also don't forget, these trucks are famous for the keyswitch not returning to the proper position after the engine is started. After you start the engine, lightly wiggle the key back and forth and see what happens. This will usually affect the wipers and the guages, but can also affect other circuits.
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Postmaster
Joined: Feb 2011
Posts: 3,560
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my experience with the ignition switch wiggle is that it only affects circuits that are switched by the key. that means it won't affect brake lights or hazard lights, but will affect turn signals, gages, wipers, etc.
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