I have a 1978 F100 LWB Auto with a 302....When I put the truck into reverse the reverse light flash for a split second and go out....What could be my issue. Where is the reverse light switch??

 

Sounds like you need to adjust the switch. It's mounted on the side of the transmission where the shift linkage hooks up.
There are two screws that attach it to the side of the tranny. loosen these screws and rotate the switch to adjust.

 

This is what the switch looks like,

 

thank you Mike thats a huge help

 

See that little hole on the side of its casing? Loosen the switch and insert a paper clip in there to align its internals.

 

my reverse lights dont come on at all would this fixed mine?

 

Possibly, but you need to perform the routine trouble shooting steps to make sure that's what the problem is.
First, check the fuse for that circuit, then make sure the bulbs are good, check the sockets and in particular, check the grounds. A lot of electrical gremlins in these trucks can be traced to poor or bad grounds. See if you have voltage at the switch. If all that is good try adjusting the switch. If still no-go, check the switch itself to see if it's bad. Then check the wiring to the back up lights.
Just a note, usually if it's the adjustment you'll also have starting problems. You have to "jiggle" the shifter to get the strarter to spin because the back-up lights and neutral start are in the same switch.
If your truck is a '77 or earlier the switch is mounted on the steering column, not the transmission. That's '78-up.
BTW welcome to FTE, lots of good, knowledgeable people here (and a few grouches) more than willing to help or answer your questions.

 

Slight hijack but still on topic. My truck was converted from auto to manual. Is the reverse switch in the transmission? Need to get some reverse lights working on this even if I have to custom wire it all.

 

depends, what year is your truck? Most manuals have it on the top cover somewhere (np435 and t18/t19) not sure if you have a 3 spd might be on the top of column tube, under dash thats were the older automatics were, so it may have never been modified in your truck.

 

I have the Np435. The truck is a 79 but I think the tranny came from a 76. I was going to run a relay for the reverse lights since I will be putting thin driving lights back there. Going to have it where it's controlled via the reverse switch, off, or manual operation with a 2 position switch. Just didn't know where the reverse switch was located.

 

[quote=mikeo0o0o0;10673630]Possibly, but you need to perform the routine trouble shooting steps to make sure that's what the problem is.
First, check the fuse for that circuit, then make sure the bulbs are good, check the sockets and in particular, check the grounds. A lot of electrical gremlins in these trucks can be traced to poor or bad grounds. See if you have voltage at the switch. If all that is good try adjusting the switch. If still no-go, check the switch itself to see if it's bad. Then check the wiring to the back up lights.

Well the lights worked a year ago when we took the bed off to paint it, the ground wire goes to the same spot as the brake lights and they work, the windsheild fluid works and thats on the same fuse, the bulbs are new, and the truck will start in neutral so that should rule ou the switch.

 

Well the lights worked a year ago when we took the bed off to paint it, the ground wire goes to the same spot as the brake lights and they work, the windsheild fluid works and thats on the same fuse, the bulbs are new, and the truck will start in neutral so that should rule ou the switch.

 

The reverse switch is on the drivers side top of the tranny just below the shifter. Hot in one side the other out to your reverse lights you can unplug the original auto back up lights behind the gauges and wire in the lights to the switch so they work off of the factory harness. The wire is more than likely black with a red stripe.

 

I tryed to align m#the internals on my swich with a paper cip but i could not get th paper cp to go in very far at all no matter how i turned the casing

 

I losened the bolt and put a paper clip in the hole and tryed to align the internals but it doent go in very far.