I copied a picture of one of Phils diagrams on classic Broncos.com I hope he doesn’t mind.
Mine is a 68 but I think the coloring on the wires is basically the same.

Can someone tell me what color(s) to run to the (3rd) red brake light and which color(s) to run to the (3rd) back up light?

Passenger
Green
Brown
Blk/Red

Drivers
Yellow
Brown
Blk/Red

License plate bulb
Brown

The third brake light basically has one wire for the RED light with one ground wire
And basically the same for the reverse light, one wire with a ground as well

It’s listed as cargo lamp but I want to hook it up as my reverse light!

Thanks!

Brown is marker/taillights. Just hooked mine up yesterday. Yellow is stop.

I used the wiring diagram at seabiscuit68.tripod.com.

Adam

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So if I want the Tail light to act like a marker light and a brake light then I need to wire both the Brown and Yellow wires to it?

And I’m assuming the black and red is the back up light wire?

I wired up a similar light mounted on the top back part of my roll bar. I ended up running a separate brake light from the switch back to the 3rd brake light because it kept blinking with the turn signal from one side or the other. Backup was as easy as pulling from the wires in the tail-light, and running hot wires from each brake light wasn’t going to work. FYI.


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Thank you Gentleman!

Black-red is reverse light.

If you don't want the 3rd brake light to flash with turn signals you need to run a new wire directly from the brake light switch (before it gets to the turn signal switch).