Tail light wiring harness question
Thread Starter
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Posting Guru
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From: Santa Monica, CA
Tail light wiring harness question
I'm splicing the pigtail onto the wiring harness of my new-to-me bed for my 66 F100 shortbed. The PO cut the wires rather than disconnecting the plug. I have a yellow, green & 2 brown wires. The yellow & green are obvious but does it matter which way the 2 brown wires are connected? Thanks for the help!!
Fleet Owner
Joined: Jun 1999
Posts: 24,552
Likes: 74
From: Creedmoor, North Carolina
3 wires is correct, I don't recall which is which but it doesn't matter.
1 is tail light, license plate.
The other 2 are left & right turn signal/ brake. The brake & ts share so turn the ign. switch on move the ts to start it flashing and with a circuit tester you can correctly identify left or right at the rear.
Piece o cake.
John
1 is tail light, license plate.
The other 2 are left & right turn signal/ brake. The brake & ts share so turn the ign. switch on move the ts to start it flashing and with a circuit tester you can correctly identify left or right at the rear.
Piece o cake.
John
Thread Starter
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Posting Guru
Joined: Nov 2008
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From: Santa Monica, CA
3 wires is correct, I don't recall which is which but it doesn't matter.
1 is tail light, license plate.
The other 2 are left & right turn signal/ brake. The brake & ts share so turn the ign. switch on move the ts to start it flashing and with a circuit tester you can correctly identify left or right at the rear.
Piece o cake.
John
1 is tail light, license plate.
The other 2 are left & right turn signal/ brake. The brake & ts share so turn the ign. switch on move the ts to start it flashing and with a circuit tester you can correctly identify left or right at the rear.
Piece o cake.
John
Thanks. If anybody knows specifically what each colored wire is for, that would be helpful.
Thanks again.
Elder User
Joined: Apr 2008
Posts: 619
Likes: 1
From: Montpelier, VA
If you look at this thread and go to post#6, you will find a wiring diagram that should answer all of your questions. You need Adobe Acrobat Reader to view the file. I saved a copy of it on my hard drive and laminated a printout for reference.
Mark
https://www.ford-trucks.com/forums/1...horn-wire.html
Mark
https://www.ford-trucks.com/forums/1...horn-wire.html
Thread Starter
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Posting Guru
Joined: Nov 2008
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From: Santa Monica, CA
If you look at this thread and go to post#6, you will find a wiring diagram that should answer all of your questions. You need Adobe Acrobat Reader to view the file. I saved a copy of it on my hard drive and laminated a printout for reference.
Mark
https://www.ford-trucks.com/forums/1...horn-wire.html
Mark
https://www.ford-trucks.com/forums/1...horn-wire.html
Posting Guru
Joined: Jan 2000
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From: colbert washington
According to the 66 wiring diagram I have yellow black should be your rt side directional and the green should be the lft side directional the brown is for tail and license plate lights.
Fleet Owner
Joined: Jun 1999
Posts: 24,552
Likes: 74
From: Creedmoor, North Carolina
37 Your truck has backup lights, that fourth wire is for that.
Get a circuit tester like this one, it makes tracing wires much simpler.
John
Get a circuit tester like this one, it makes tracing wires much simpler.
John
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Elder User
Joined: Apr 2008
Posts: 619
Likes: 1
From: Montpelier, VA
John, I'm not aware of any '66 having backup lights. I thought backup lights were '67 and up.
Mark
Mark
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Lead Driver
Joined: Jan 2005
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From: Orcas Island Wa.
I just did this last week when I put the new bed on my '59. I think he has 2 brown tail light wires is because he is past the part where the brown wire splits into two. One for each side and they're the same circuit, so really you're both right as the brown wire at some point splits to feed the right side tail light but in some ways it's the 'same wire'. My .02
Posting Guru
Joined: Jan 2000
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From: colbert washington
If he started to check his bed wiring some where after the molex connector with the 3 wires comming from the front of his truck. He may have more than 1 brown wire as a brown wire goes to each tail light and another would go to the license plate light. That would be a total of 3 brown wires depending on where he was looking.
Postmaster
Joined: Mar 2004
Posts: 4,375
Likes: 5
From: seattle
The wiring for the rear lights that runs along the frame rail has 3 wires where it ends at the frame rail......green, yellow and brown. Green and yellow are right and left tail lights respectively. The brown is where the license plate light is fed off of. The light sockets/buckets ground themselves to the body/frame of the truck.
The brown is connected to each other within the harness...a simple continuity check will confirm that if its as originally made. The tail light harness that runs across the rear of the bed is the same way.
- cs65
The brown is connected to each other within the harness...a simple continuity check will confirm that if its as originally made. The tail light harness that runs across the rear of the bed is the same way.
- cs65
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Posting Guru
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From: Santa Monica, CA
Thanks guys for all the help & comments. To follow up, according to wiring diagram referenced above, the green is the left directional light, yellow is the right directional light and a brown wire also goes to each taillight plus the tag light. There is a connector right before the last cross member at the rear of the chassis. It's at that connector that the brown wire goes from a single wire to two brown wires plus the yellow & green. I didn't know that when I first posted the question. Since the 2 brown wires come from a single brown, it didn't matter which one I attached to each other. I have now attached each of the wires on the pigtail to their respective colors on the tail light harness and it all works great. Thanks again for all your help!!
ps: there is a trailer light harness spliced in there too but that didn't affect my original question.
ps: there is a trailer light harness spliced in there too but that didn't affect my original question.