Brake Lights Won't Turn Off

[antonio_santos]

Hello to all. I'm the proud owner of a 2004 Chevy Trailblazer Ext. My background is in computer systems. I'm a network/ systems engineer. Cars are a different world for me. I'm having a problem so I am hoping that somebody could provide me with some technical assistance. The problem is that basically, my brake lights won't turn off after I turn off the vehicle. It does this intermittently. I haven't been able to identify a pattern. When I turn off the vehicle, sometimes the brake lights won't turn off and sometimes it will. I don't know what is causing this. I already checked the brake fluid. I thought that maybe the vehicle was telling me that it needed brake fluid. The brake pads and rotors are in good condition. Any thoughts? I don't want to visit the stealer (I meant dealer) Thanks.

 

[BO TIE SS]

Brake lights will function whether the vehicle is on or off.

If you pull back on the brake pedal, with that turn them off?

 

[The_Roadie]

It's simply a misadjusted switch on the brake pedal. You can replace it or fiddle with the mounting to get it to turn off. The power is there to the switch always, even with the ignition off. That explains how it can light up under your conditions.

Welcome! If you're not into the hardware side of things, any mechanic can adjust or replace that sort of switch. Escalating it to the dealer would be my last sort of advice. There are even aftermarket switches available at the parts stores for a lot cheaper. $6-12 is my recollection. Looks like this:

View attachment 22094

 

[antonio_santos]

Brake lights will function whether the vehicle is on or off.

If you pull back on the brake pedal, with that turn them off?

I understand that the brake lights will function whether the vehicle is on or off. The problem is that the lights are always on even if the vehicle is off and the brake pedal is not being pressed. This is a problem because I'm assuming that it will drain the battery if the brake lights are on all night.

I haven't tried pulling back on the brake pedal. I will try this later on today.

Thanks.

 

[The_Roadie]

This is a problem because I'm assuming that it will drain the battery if the brake lights are on all night.

That's right, but you can always pull front fuse block fuse #12 for peace of mind.

 

[antonio_santos]

Brake lights will function whether the vehicle is on or off.

If you pull back on the brake pedal, with that turn them off?

Yesterday, my vehicle was doing it again. As I mentioned, it is an intermittent problem. I got off from work at about 5:30 pm. I drove home (about half an hour drive) and when I arrived, I turned off the vehicle, checked the brake lights (they were off), and then went inside the house to do my stuff - had dinner, check my mail, etc. About an hour later, I went outside to throw the trash and I noticed that the brake lights were on. This time, I pull back on the brake pedal and that didn't worked. The brake lights were still on. I had to start the vehicle, press the brake pedal, release the brake pedal, and turn the vehicle off. The brake lights were off again. I went inside home again. Before going to bed, I went outside to check on my vehicle. The brake lights were on again. I had to repeat the same procedure (start the vehicle, press the brake pedal, release the brake pedal, and turn the vehicle off again).

I really don't know what is causing this. Is it some type of electrical problem?

 

[The_Roadie]

I really don't know what is causing this.

We do, and advised you already. Don't you trust the answers?

Is it some type of electrical problem?

That's what I said, and I have a small bit of experience with the electrical systems in the truck (actually, 7 years now). Start with the switch. Are you not able to change the switch?

There's a tiny chance that the pedal is able to come up higher and get the switch to turn off after you start the engine and press on it, compared to just pulling up on the pedal. That might be a mechanical problem. Just take a flashlight and bend over and LOOK at the top of the pedal assembly where the switch is. See if there's some material up there or a french fry bag or a dead mouse tail or something that mechanically looks out of place.

But otherwise, start with changing the switch.

And pull the fuse when you're not driving it to make sure if they come on that your battery doesn't get drained.

 

[antonio_santos]

We do, and advised you already. Don't you trust the answers? That's what I said, and I have a small bit of experience with the electrical systems in the truck (actually, 7 years now). Start with the switch. Are you not able to change the switch?

There's a tiny chance that the pedal is able to come up higher and get the switch to turn off after you start the engine and press on it, compared to just pulling up on the pedal. That might be a mechanical problem. Just take a flashlight and bend over and LOOK at the top of the pedal assembly where the switch is. See if there's some material up there or a french fry bag or a dead mouse tail or something that mechanically looks out of place.

But otherwise, start with changing the switch.

And pull the fuse when you're not driving it to make sure if they come on that your battery doesn't get drained.

Thank you everybody for your great help. I will try the switch this weekend and let everybody know how that went. Sorry to be a pain but as I mentioned, my world is computers. I don't trust dealers, but I do trust 100% the users of this forum.