I have a 1972 F100 that I just had painted. Before, I had hooked the bed lights up by myself. However they were unhooked for painting. Now, trying to redo them, there are some issues:
1. Out of the 4 wires, 2 of them blink with the right blinker. None flash with the left one.
2. My clearance lights on top blink with the right blinker. They also blink with the hazards (which could be normal but I don't remember that happening).
3. Only one wire lights up for the tail lights (its one of the wires that also lights up for the right blinker).

The reverse lights are fine. Also, if I turn the clearance lights and tail lights on, all the lights that blinked with my turn signal now just stay solid when I hit the right turn signal switch. Moving up the frame, following the wires I did find some wires that branched off with a plug toward the front of the cab that was not plugged into anything... I couldn't find where it goes to and I don't know if it was plugged in before or not... Any ideas as to what's wrong? Thanks in advance.

 

You'll have to troubleshoot on your own by referencing wiring schematics and using deductive reasoning. Us troubelshooting it from the opposite side of the screen is darn near impossible.

The turn signal switch is the usual culprit but that's just a guess.

Refer to pages (sheets) 5, 6, and 7 on this page: 1972 Ford Truck Wiring Diagrams - FORDification.com

 

Alright. Thanks. I have a wiring diagram printed... I'll start looking.. Any idea how I would test the turn signal switch? I'm not very familiar with wiring. I know these trucks are simple but I just don't know where to start.

 

There should be ONLY 4 wires going to the back end. Anymore, and someone has hacked it up.
I would start at the firewall where the four come out(should be a plug). Unplug it and see if you get proper sequences. One reverse, one parking, a Left and Right turn/brake. Anything that is hooked up to those four wires going to the back should not be there.

I agree, the turn signal switch can be a cause of issues, but sounds like someone has wired in a few things to the wrong place and it is all screwed up.

Take the diagrams and slowly trace everything. It is hard to diagnose over the internet, but at least we can help lead you in the right direction.

 

First check the grounds and clean/reseat the plugs and connections. Do a visual inspection for tapped wiring or other hacked wiring. Test.

Then begin by verifying the circuits - which ones "behave" correctly and which ones do not. Write'em down. Then analyze the diagram(s) and evalute what they may have in common. After that verify input and output signals - is the voltage signal present when it is supposed to be? Or do other circuits energize when not supposed to? Write down your results and deduce.

 

On the turn signal - does your front turn signals work - one test for the switch.

Also, I checked a lot of wiring issues at the connection just inside the firewall on the engine side. Your tail, turn, brake lights run through that plug. You can plug a tester into the correct connections in it (determined from the master wiring diagram) and see what happens.

And, now unmolested is your wiring from the cab back to the tail lights? - Towing and extra connections can really make for a mess. Clear out the non-stock stuff and get back to original and see how things go.

But the master wiring diagram is your friend. They are available at Fordification.com

Jeez: did not type fast enough. Mine is essentially a duplicate post.

 

Alright. Thank you all for the posts. I actually just got it fixed yesterday. I knew my headlights were not working so I pulled those and the grounds were not on either one. Hooked them up and the headlights came on. Then plugged in the front turn signals. After I did that, everything stopped acting weird... I guess they all feed off of eachother which I did not know. I'm glad it's all fixed now.

 

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