Brake lights won’t turn off

Hi!

After not driving my truck for about 24 hours, my brake lights randomly turned on without my keys being near the truck.

I unplugged and removed the switch, the fuse (for the brake lights) by the wheel, and the fuse under the hood. The brake lights are still on…

The only thing that turned them off was unplugging the battery.

what could be the issue?

 

Brake lights or Tail Lights?

It makes a difference.

 

im sorry. Brake lights. Not tail lights.

 

This may be broken, it defaults on when broken.

https://www.youtube.com/watch?v=xAXx-V2IzpI

 

A trailer brake controller can also turn the brake lights on. Either if the manual slide isn’t fully returned, or a failure of the controller.

 

I completely removed this piece and the brake lights are still on, thus I’m thinking this isn’t the cause or the lights would turn off with this disconnected, right?

 

He’s saying that an open circuit of the brake light switch = lights on. I haven’t verified, but I believe he knows his stuff. You could try jumping the pins of the connector with a paper clip to see if the lights go out. Just be gentle, don’t ram it in and damage the pins

 

If you pulled the 10 amp fuse for the stop lights and removed the stop light switch then there shouldn't be any other power source for the lights.

 

Other than through a trailer brake controller, which is why I mentioned that.

 

Yes. Thanks for the additional point.

 

Skid Control with Actuator also provides juice to lamps

...and has it's own fused direct battery juice.

 

Maybe that relay is stuck closed. Stop lp ctrl relay

 

OP, does your Taco have this:

 

Odd thing, today mine started having a similar issue.

I was running around stopping here and there, the last stop I noticed my 3rd brake light is lit. Check the rear, brake lights are also lit. Check to see if I had my headlights on, no.

Got home, they’re all still lit. Turn headlights on and off, stomp the brake pedal about 20 times, I could see them flash off then right back on. Check the front, nothing lit, checked the back, now they’re all off. Stomp the brake pedal, now they’re stuck on again. Start and stop the engine, now they’re off. Locked the doors with the door switch, now stuck on again. Fiddled with it until they turned off, locked the doors and closed the doors. Well it’s off now so I won’t need to hook up the battery charger.

 

Unless they decide to turn back on by themselves.

This sounds like a switch problem.

 

This statement here has me wondering. You mean by simply locking the doors, the brake lights came on? Ehhhh, What? / That’s no good. No good at all

 

I’m thinking the same, it’ll be the first thing I look at this weekend. I won’t need to drive it until then.

Except this, I suppose a faulty switch could internally short by slamming the door or sneezing too hard.

It’s probably unrelated but, I also was noticing an intermittent no acceleration issue. It did it 3 times today that I noticed. So I’ll hook up the obd this weekend too.

 

That could be related. Brakelight switch is a input to the pcm so it could be cutting fuel or throttle if it thinks you're applying the brakes

 

Remembered last weekend I filled the gas tank, drove straight home & parked it all day Monday. I'm wondering if filling the tank, gasoline expanded like it does, and damaged whatever gets damaged when we overfill the gas tank.