[MXmaniac]

This is weird. I'm looking at the wiring diagram for the truck, and like you guys say, there is no such thing. However, on my truck, its there. When the brake lights don't work, I can wiggle that wire and I hear something inside it click, like some contacts in there. After that the lights will work. The guy at NAPA knew what it was though, and he told me he has a '72 C-10 he's working on. I'm all confused because its on my truck, and looks factory, and the guy at NAPA knew what it was. But its not in the wiring diagram and you guys say it doesn't exist.

When I step on the brake, the right turn signal indicater in the dash lights up and stays on as long as I'm pressing the brake pedal. I think this is telling me there is a problem in the system. Could that be what this "brake light controller" is for?