US Shift and reverse lights

[stretch]

Alright, checked the search and once again this seems to be a ”me” problem. US Shift Quick 4. Verified the wiring is correct, start circuit from the starter relay, one from the key, 12v in run and I spliced the two bulk/red backup lamps to the white bkup lamp wire coming from the quick 4. The problem is that the backup lights are on constantly. Park, reverse, drive, it doesnt make a difference. I’m sure it’s something simple, but I can’t figure it out.

 

[DirtDonk]

What two wires did you splice together? Are they the ones from the factory harness? That’s what it sounds like, because one has power with the key on and the other goes to the back up lamps. So you affectively connected the back up lamps to the ignition switch.
If that’s what I’m hearing that is.

Is there only one wire from the shifter? Should be another I would think. If it’s a switch, but I’m not sure how that set up works.
Are there any online instructions for it?

 

[stretch]

You know Paul that’s probably the only two wires that I dint check. I bet you are correct. I just assumed two wires , one for each tail light. Power is on all the time. I’ll check that first thing tomorrow.

 

[DirtDonk]

I’m sure that’s it then.
You can be assured that Ford would not run two discrete wires all the way from the front to the back when one would do the job. Normally they would run a single wire back to at least the drivers corner, then split it into two to feed the two separate lamps.
Shorter wires, less cost, less hassle.

Whether it’s an automatic with a neutral safety switch combination, or manual with a simple plunger type switch, it just opens and closes the circuit between the two wires.
At some point I think they even changed the color of the wires so you could tell it a glance which one was switched power and which one went back to the lamps.
Thought they actually did it in 79, but if you have two black with red stripe wires, either it was later or it was a running change.

 

[stretch]

Paul

just let you know that that took care of it. As soon as I read your post it was one of those slap your forehead moments. I appreciate the input.

 

[DirtDonk]

Fantastic! Glad you got it worked out.