My truck had a flat bed on it with trailer lights wired underneath. They didn't work. The only thing hooked up when I got it were the parking lights, and they were just held on with electrical tape. The stock harness was cut and wired to these lights. So I don't have the factory stuff to go on here.

My wiring diagram according to my haynes diagram says my truck should have a green wire for the right hand blinker, a green spliced to light blue/black for the left hand blinker, a brown wire for the parking lights, a black wire for ground, and a black/red wire for the reverse lights.

All I have is a wiring harness with the plug for the fuel sender, an extra plug with a whitish wire that isn't hooked up to anything and looks like it never has been, that branches off the harness at the same point as the fuel sender, and then the main harness that goes back towards the taillights, and it has a black/red striped wire, a brown wire, a green wire, and a brown/yellow striped wire. I'm guessing brown is parking lights, black/red is reverse, but not sure about the green and brown/yellow striped wire. My guess, of course, is that the hanes is wrong and instead of blue/black the left hand blinker is brown/yellow, since thats the only wire left over. But I thought I'd ask on here to see if anyone knew for sure.

 

Agreed, Haynes manuals are often incorrect, or inconsistent with regard to color within the same diagram. Most factory wiring diagrams are available here: 1973-1979 Ford Truck Wiring Diagrams & Schematics - FORDification.net

 

I looked through that site last night and could not find the tail light diagram, I looked through all 10 pages. I only have a very small netbook and its very hard to view those diagrams, they are either full screen and I can't see any of the writing, or at full size I can see like a tenth of the diagram at a time. And of course those diagrams aren't exactly easy to follow to start with.

 

'78 is incomplete (assuming that's what you're working on, based on your profile) but the '79 should be the same for this section. According to page 6:

BROWN: running lights for both sides (100% sure on that one)
GREEN: right-hand turn signal / brakes (same filament in the bulb)
YELLOW with BLACK stripe: left-hand turn signal / brakes

Page 7:

BLACK with RED stripe: backup lights

Is the YELLOW with BLACK wire what you're calling the "brown/yellow striped wire?" If so, you should be good.

 

you dont say what year your working on but try this FORDification.net they have some complete wiring diagrams and if i remember correctly and i usualy dont all the f series were the same on tail lights

 

Did you not read any of this thread?

 

yeah its sorta black, I was calling it brown because its not quite as dark as the other black wire. I tried to give you reps but it says I must spread them around. lol. thanks!