Brake light controller?

[MXmaniac]

I need help finding what I believe is called a brake light controller(that's what the guy at NAPA called it). My brake lights have been kind of hit or miss and I have found the problem to be a little relay box under the dash. Not the brake light switch itself, but the relay box. I believe the contacts in there are sticking sometimes. My problem is that I can't seem to find one available. Does anybody know where I could find one?

[cdowns]

only relay i know of in that areais the horn relay and it has nothing to do with any lights// try running a ground wire from your bed to the frame rail or if the original is in place remove it clean it and reinstall it

[topdog]

Do you have a third brake light ? They have a controller that keeps your third brake light from blinking when you use your turn signals. Maybe thats what hes talking about. If you don't then I agree with cdowns a bad ground can can cause all kinds of trouble. Good luck and please don't drive it till your sure its fixed.

[Longhorn Man]

Anyone who knows how to do basic wireing could hook up a third brake light without that stupid controller.

The brake light rout of power goes from the fues box, to the switch on the pedal, to the turn signal (very common for the hit and miss operation you describe) and then it goes out to the tail lights. No controller, no relay, no stupid gizmos... nothing.

With an assistant watching the tail lights, sit in the cab with your foot on the brakes... wiggle the turn signal lever very slightly up and down. If you acuate the signal with the ignition in the off position, then that side light will just turn off. Try lightly pushing it forward and back too.
If all is good so far, place the signal in one of the on positions (as in turn signal on) and try the wiggle up down forward back... then the other direction, same test. your assistant is looking for both lights to go off.
If it passes this test, then suspect a bad ground on the bed... esp problematic if your bed has a wooden floor, or, if the bed has been removed any time recently.

[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?