brake light switch power

[77pony]

I have intermittent power to my brake light switch. When I do have 12V to the switch, it works fine. I think the power comes from the headlight switch. Do you suppose there's a breaker in the headlight switch that is malfunctioning, similar to how they act up sometimes and make your high beams cut out?

I hate just throwing parts at a problem so I thought I'd see if anybody has run into this before. -al

 

[graniteguy]

Pretty sure it comes from steering column. Same power as blinkers.

 

[Viperwolf1]

Power comes from the headlight sw and there is a thermal breaker on it. Ask yourself why the thermal breaker is hot enough to open. Might have something to do with the park or dash lights, which are also on that circuit. Which of those bulbs is not working?

 

[77pony]

So are you saying that the breaker will flip if one of the lights is burned out? It wouldn't require a short somewhere in those circuits? I do have one of the side markers that occasionally goes out, until I jiggle the bulb. But when I lose power to the brake switch, I don't also lose power to the parking lights. So the problem must be between the headlight switch and the brake switch? I need to check a couple of things. -al

 

[Viperwolf1]

So are you saying that the breaker will flip if one of the lights is burned out? It wouldn't require a short somewhere in those circuits? I do have one of the side markers that occasionally goes out, until I jiggle the bulb. But when I lose power to the brake switch, I don't also lose power to the parking lights. So the problem must be between the headlight switch and the brake switch? I need to check a couple of things. -al

I'm saying the breaker is opening because it's getting hot. It's getting hot because it has too much current flowing through it. It has too much current flowing through it because something in those 3 light circuits (brake, park, dash) is shorting to ground. A short to ground will make current go directly to ground, not through the bulb(s) it's intended to go through. Thus the bulb(s) in that circuit will not be on when the short is happening.

 

[77pony]

Yeah I knew that's how it worked but that's not what I thought you said.

Anyway, shouldn't I lose dash/parking lights at the same time if the breaker is opening? I don't, I only lose power to the brake light switch. -al

 

[Viperwolf1]

Anyway, shouldn't I lose dash/parking lights at the same time if the breaker is opening? I don't, I only lose power to the brake light switch. -al

If the breaker is open you will lose all those lights. If that's not the case, look for a problem with the red wire.

 

[77pony]

OK that's what I thought. Thanks for your insight. -al