Tail light wiring?

[Carl]

Been trying to trace down the source of my Lt taillamp not working. Somebody installed a trailer hookup and the wiring is just a mess. The left taillamp was totally blank, and now I've got the backup light working as well as the running lights. Still no Lt turn signal or brake light though. Some wires were broken and I soldered them back together. Others just lead to nowhere.

I've found four wires leading in from the front of the truck. Do I have this right?
-black/red.....backup?
-brown......running/parking lights?
-green.....????? right turn/brake?
-yellow.....????? left turn/brake?

The brown has me kind of puzzled. There is one wire coming from the main harness, (which was totally disconnected from anything) but there seems to be two brown wires on the input side of the factory plug/harness. I can get the running lights working by attaching either brown wire. Was one un-used from the factory on mine, but maybe used on other trucks with different options? The other strange thing is that the running light on the left blinks when I hit the left turn signal switch and have the headlights on at the same time. Maybe so the side marker light blinks at night too?

Assuming the brown is working right, that means I'm down to the left rear brake/turn not working. The left front will blink with the hazzards on, but not with the turn signal. Could there be anything other than the left rear wiring causing the issue? The switch itself?

[fordman]

the brown wire at the firewall plug is only one wire in that plug that is brown. so a secondary brown wire has been added. the brown is tail lights you are right. white is ground. yellow and green are turn signals. it sounds like a bad ground or the wires aren't working right. it could also be in the turn signal switch. once you are sure the bulbs are good and all the wires are hooked up right. then you check to see if power is going out of the column and then trace it back to where the power stops in the wiring. if it doesn't have power going out but power going into the column then the switch has something wrong with it.

[Carl]

Spent a large chunck of this weekend and got most of it working.

-running lights work
-backup lights work
-brake lights work
-hazard flashers work
-Left turn signal does not work.

I can only guess that it's the turn signal switch itself since all the bulbs light up under other circumstances. Unless somebody has some other idea.

[mr_josh]

I think it pretty much has to be the at the turn signal switch, because the same wire is used for brake and turn signal power.

[fordman]

probably the switch then.

[rangerdanger]

what color is the power feed to the brakes and the indicators? And where does it come from?

[Carl]

what color is the power feed to the brakes and the indicators? And where does it come from?

-black/red.....backup
-brown......running/parking lights
-green.... right turn/brake
-yellow.... left turn/brake

This ended up being correct. One thing that I didn't realize was that the housing had to be attached to the body to be grounded. These four wired came to the rear of the truck in the factory harness and get split/diverted via various connectors as the harness exits the frame rail near the left rear.

[fordman]

i think the power feed color is black with red stripe. its wire number 810 on the diagrams i think.

[Carl]

i think the power feed color is black with red stripe. its wire number 810 on the diagrams i think.

Nope, as noted above black/red is for the back-up/reverse lights.

[fordman]

what year are we talking about?

[Thunderfoot]

what color is the power feed to the brakes and the indicators? And where does it come from?

The power wire for the brake lights (at the brake switch) is a Red wire (284), it comes from the fuse box via a junction with the power wire going to the Turn Signal flasher (same power circuit feeds both) here is were it turns into a Red/white striped wire (383) to the fuse box itself. After the Brake switch, the power wire turns to a Red/black striped wire (810) to the TSS. For reference http://www.fordification.com/tech/wirin ... _81-85.jpg

[fordman]

ok that is where wire 810 branches off of. i got the color mixed up too. it is red w a black stripe. oops.

[Carl]

All I know is what I found on my 1970.......as noted above. Don't know what it looks like on the TSS, only the end that pops out of the frame at the rear.

[fordman]

ok i didnt know that is where we where talking about. my mistake.

[Thunderfoot]

All I know is what I found on my 1970.......as noted above. Don't know what it looks like on the TSS, only the end that pops out of the frame at the rear.

Yes the colors are different after the TSS out to the lights, but the power source is before the TSS which is what I noted above.