Brake lights stuck on no matter what unless battery disconnected

[1988montecarloss]

This is in a 91 s13 if that matters, but Brake lights stayed on after I shut the car off the other day and I checked the switch and noticed the plastic plug in the brake pedal that activates the switch had fallen out so I put a nut and bolt in it to activate the switch again and it fully depresses the switch like it should and the brake lights remained on. So I then unplugged the switch completely and they still remain on and even after pulling the brake light fuse they remain on as well so im thinking there has to be a short in the wiring somewhere.

Could the piece falling out and keeping the brake lights on cause the wiring to short out? They were stuck on for about an hour or so before I noticed but I don't think that would cause that. If it is a short where does the brake light wiring run through so I don't have to tear the whole car apart looking? Yes I know I should search but my internet router has also recently taken a shit -_- so I'm trying not to use all the data on my phone


Any help is greatly appreciated 😁

[1988montecarloss]

I did take the wing off the car the other day which involved unplugging the third brake light but no water or anything has gotten into the trunk so I don't think that could be causing my issue, unless the third brake light wiring is necessary for some reason

[EnnEssEnnKAT]

Check behind your brake pedal and find the brake light switch. Press the brake light switch and see if it goes off. There's a plastic push pin like thing that sits behind the pedal and hits the switch when you press the brake (for the light) and if the pin thing falls out, the brake light stays on.

[1988montecarloss]

Check behind your brake pedal and find the brake light switch. Press the brake light switch and see if it goes off. There's a plastic push pin like thing that sits behind the pedal and hits the switch when you press the brake (for the light) and if the pin thing falls out, the brake light stays on.


Like I wrote in the first post the switch is pressed down as far as it will go and they remain on, unplugging it should turn them off too id assume and it doesnt

[1988montecarloss]

Does the wiring for the brake lights run through the fenders at all? I have my harnesses tucked up so the tire hasn't chafed any wires but maybe the fender has rubbed through them somehow?

And am I correct in thinking if it's unplugged they would turn off if it was the switch?

[kruked]

Replace the switch itself. It's not expensive and if it doesn't solve your problem, return it. I do believe it to be the switch itself though. Unplugging the sensor would theoretically be like the switch being activated by pressing on the brake peddle.

Having the third brake light unplugged will not cause your issue.
The wiring for the brake lights runs solely through the cabin... Unless you have custom brake lights in the front of your car, thus resulting the wiring to run through your fender wells.

[1988montecarloss]

Replace the switch itself. It's not expensive and if it doesn't solve your problem, return it. I do believe it to be the switch itself though. Unplugging the sensor would theoretically be like the switch being activated by pressing on the brake peddle.

Having the third brake light unplugged will not cause your issue.
The wiring for the brake lights runs solely through the cabin... Unless you have custom brake lights in the front of your car, thus resulting the wiring to run through your fender wells.


Alright thanks, went to a parts store today to get a switch and the one they listed looked the same but had bigger terminals on it so it wouldn't plug in, going to go to the Nissan dealer tomorrow to see if they have the right one

[EnnEssEnnKAT]

The fuse +12 V goes to the brake light switch first, and no where else. If it isn't the switch you have a short to 12V. Brake light fuse is in the kick panel. Good luck

[kruked]

So I then unplugged the switch completely and they still remain on and even after pulling the brake light fuse they remain on as well so im thinking there has to be a short in the wiring somewhere.

Could the piece falling out and keeping the brake lights on cause the wiring to short out? They were stuck on for about an hour or so before I noticed but I don't think that would cause that. If it is a short where does the brake light wiring run through so I don't have to tear the whole car apart looking?


My dumb ass over looked this portion.

That wire could generate enough current to build up heat. How long though is the question. An hour could be enough time but who really knows.
Did you bother to look at the fuse when you pulled it to see if it was blown? If it is blown, then that could be an indication that there could be some wires burnt up. If it is not blown, then it looks more likely that it's the switch.

The wiring for the brake lights runs along the driver side of the car. So does everything else. From the SMJ, everything runs along the driver side then wraps around to the passenger side and dead ends at the passenger
"door ajar" switch.

[1988montecarloss]

The fuse +12 V goes to the brake light switch first, and no where else. If it isn't the switch you have a short to 12V. Brake light fuse is in the kick panel. Good luck

My dumb ass over looked this portion.

That wire could generate enough current to build up heat. How long though is the question. An hour could be enough time but who really knows.
Did you bother to look at the fuse when you pulled it to see if it was blown? If it is blown, then that could be an indication that there could be some wires burnt up. If it is not blown, then it looks more likely that it's the switch.

The wiring for the brake lights runs along the driver side of the car. So does everything else. From the SMJ, everything runs along the driver side then wraps around to the passenger side and dead ends at the passenger
"door ajar" switch.

Thanks guys, fuse was still good so hopefully I just need a new switch, going to try to get one today

[jdm-specs]

If u did pulled the switch and fuse and stays on. There could be another 12v power source being induced/shorted into the brake light harness. Or it's a ground feed back through the brake map circuit.

Highly recommend to see if it could've happen. After a recent install/removal. If it happened out of no where then you should down load the nissan fsm and find out how the harness routes or if there is any intermediate connector between the pedal area to the brake lights to isolate one section at a time