putting the brake controller in

[yellomalibu]

I'm putting the brake controller in the 84 C10 and having trouble verifying which wire to attach the brake light (actuating) wire to in the truck.

Would either the orange or white wire work just as well? These are the two wires coming off the brake light switch at the pedal. I'm assuming that it's a normally open switch, and when the brake pedal is depressed, the switch closes - completing the circuit - in which case either wire would work, right?

It's hard to figure out without a helper or a test light. the volt meter has completely kicked my butt trying to hold it on the contacts, press the brake pedal, and try to see it - all at the same time.

*edit*
I just looked at a schematic, and the orange wire appears to come right from the fuse... so if I tap into that one, it would be hot all the time. I think I need to tap into the white one, on the other side of the switch, so its only hot when I hit the brake pedal.
...but I still want to use a test light to be sure before I go messing with the wires. They are in a location where repairing it would be more of a pain in the ass.

[squirrel]

should be white

[Rocketman]

What he said^^^^^^Don't forget to put a circuit breaker in the power wire feeding your controller