D/S Back-up light is on???

[Doug F]

Like Pickly, I have an issue with one back-up light that comes on when I turn the key to on, and it stays on when I turn it to run as well.

Truck: 1967 F100 4wd
Trans: NP 435 4 spd.

My issue started when I was tracing electrical gremlins with the taillights, and was at the post on the rear of the ignition switch. I thought I had shorted something out inside the switch and now I know that is not true, since I installed a new switch. I am guessing it is the infamous black with red wires... 140, 140A wires and/or the Black w/ Green 297 wire from the rear post of the ignition switch that runs to the fuse panel.

As a side note, I cannot find the 140 or 140A wires that connect to the back-up light switch; I JUST found the back-up light switch on the trans! It was buried under dirt and grease cake and had no wires attached to it.

I do remember there were some cut wires just in front of the firewall, I am thinking they were Black w/ Red... Maybe I closed a loop without knowing it?

Anyone have any ideas?

Thanks.

[Thunderfoot]

With that trans it would of had a short wire that went from the switch on the trans to the connector at the base of the column. (see attached pic) This connector is there on all trucks, if it is a column shift manual the switch is mounted on the column where the shifter rods connect and this plug would plug right into the switch. With an automatic there is a jumper wire connected into this plug out side and it uses the wire connection inside where the NSS is connected at.
Anyway, if all the wires are looped together then the reverse lights will be on all the time with the key on, so check those black/red striped wires.

[Doug F]

Hey thanks,

Mine didn't have anything, that's why I thought the wires were just cut for no reason and then just spliced them back together.

Tonight I re-cut the wires and ran 2 wires down to the back-up switch and completed the circuit through the switch like it should be. and it worked!

Now my back-up lights work!

[Thunderfoot]

good deal!