Guys, for the life of me I can't find any resources that show how to find the wire for the reverse lights in the back of the truck.

I just found it. The picture below is the top half of my passenger side rear light assembly. The left sideis the reverse light (at the top of the light assembly) . On my 1998 4Runner, the reverse light wire is RED with a blue stripe. The other wire is white with a black stripe. I believe that's the ground wire.

Hope this helps someone.

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If memory serves me you are correct. The lights have ground wires to them. I put LED reverse bulbs in then hooked 2 smaller LED bars on the back bumper to give me more light for backup..:-)

this is exactly what i’m wanting to do with mine as well so i’m hoping the wirings all similar in a 96 3rd gen!

Here is EWD of that circuit. You only use a small current draw LEDS. As you don't want overload that circuit. :-)

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BACK-UP LIGHT.pdf (29.0 KB, 238 views)

FYI Toyota ground wires usually are white with black stripe in all their circuits.

Old post and I only remark to offer my two cents. I hope this helps someone.

Bottom Line: Remove the old crush washer.

TL;DR
Like others before me, the backup lights weren't working. I got an OEM switch and the price was reasonable. I will note however, that the OEM and the one I got has a ball bearing at the tip which rolls freely (in the old and my new replacement one.) Whereas, some photos for the cheaper variants didn't seem to have the ball, but I'll admit those photos were not clear. Seems prudent to stick with an OEM part here. Anyway, I replaced, started the car, and 'no joy' the lights did not work. I jumpered the plug from underneath the car and the lights came on. I was stumped. I then noticed the old switch was missing the washer. Removed the freshly installed new one and stuck to the side of the transmission was the old washer. A flick is all it took. Re-installed the new switch and just *one* washer and it worked. I'll remark that an additional 2mm, the thickness of a washer, was enough to prevent the lights from coming on! Last, I'll remark that my old switch had between 170 and 200 ohms of resistance depending on how I jiggled it. Whereas the new one had full continuity. Good Luck!