Brake Warn Lamp Wires

[RustyPile]

Originally Posted by Ppardini

Well I wired it up without connecting the extra brown wire from the instrument cluster harness and the brake warn lamp works correctly so I have no idea what that extra wire is for, it's definitely factory so it had a proper use at one time.

It's not a good idea to leave a disconnected wire loose in the harness. Do you have gauges or "idiot lights"? With idiot lights, there's a brown wire that runs from the external voltage regulator back to the instrument cluster plug. It's part of the charge light circuit. But it doesn't connect there with a second wire.. With gauges, this brown wire isn't there. Instead, it's the black wire with the small amp fuse, part of the amp gauge circuit. If you have an internal regulator, this brown wire goes to the alternator.