[evanspears1]

Hey guys,
New to the forum and hoping y’all can help, I’ve got a 2016 Colorado, 4 cylinder, 2 wheel drive. I’m having a problem with the brake lights, the stay on almost constantly, they will randomly turn off but it seems to have nothing to do with the brake being pressed or not.

Symptoms:
Brake lights are almost always on.
Third brake doesn’t seem to do anything.
Can shift truck out of park without pressing pedal.
Sometimes the lights will go off and you can’t get it out of park without turning off and back on the truck.

Things I’ve checked/replaced:
Replaced the brake pedal position sensor with a new gm sensor from local dealer.
Checked fuses/relays, never did find anything specific to brake lights, didn’t find any that appeared to be bad or malfunctioning.

Im going crazy trying to figure this out so any and all help would be appreciated!!!

 

[White016]

Hey guys,
New to the forum and hoping y’all can help, I’ve got a 2016 Colorado, 4 cylinder, 2 wheel drive. I’m having a problem with the brake lights, the stay on almost constantly, they will randomly turn off but it seems to have nothing to do with the brake being pressed or not.

Symptoms:
Brake lights are almost always on.
Third brake doesn’t seem to do anything.
Can shift truck out of park without pressing pedal.
Sometimes the lights will go off and you can’t get it out of park without turning off and back on the truck.

Things I’ve checked/replaced:
Replaced the brake pedal position sensor with a new gm sensor from local dealer.
Checked fuses/relays, never did find anything specific to brake lights, didn’t find any that appeared to be bad or malfunctioning.

Im going crazy trying to figure this out so any and all help would be appreciated!!!

is there more than one switch on the pedal? Check them all. What happens if you pull the pedal up? Will that kill the lights? It sure sounds like a brake switch or it's adjustment.
Another thing to check is the bulbs in the back, sometime the dual filament ones can short feeding the running lights to brake light and visa-versa.

 

[evanspears1]

That’s the only sensor I see, and when I called the dealer it was only thing they offered, there isn’t an adjustment like the first gen trucks, its like a fork that rides on a nub on the pedal, and apparently it has to be relearned when replaced. I got access to a scan tool today and did some digging, as well as checked a few things.

-unplugged all aftermarket wiring/lighting (no change)

-checked all abs/bcm fuses (all hood)

-checked all bulbs for corrosion/shorts(none found)

-scanned for dtc (none found)

-attempt pedal position relearn (says sensor malfunction detected with either the new or old sensor)

-I can command the lights on and off individually through the scan tool.

-one section in scan tool shows volatage changing on pedal sensor when brake is applied, but another spot showsthat the pedal isn’t applied for some reason when it is, I’ll attach a video of that if I can figure outhow.

 

[White016]

That’s the only sensor I see, and when I called the dealer it was only thing they offered, there isn’t an adjustment like the first gen trucks, its like a fork that rides on a nub on the pedal, and apparently it has to be relearned when replaced. I got access to a scan tool today and did some digging, as well as checked a few things.

-unplugged all aftermarket wiring/lighting (no change)

-checked all abs/bcm fuses (all hood)

-checked all bulbs for corrosion/shorts(none found)

-scanned for dtc (none found)

-attempt pedal position relearn (says sensor malfunction detected with either the new or old sensor)

-I can command the lights on and off individually through the scan tool.

-one section in scan tool shows volatage changing on pedal sensor when brake is applied, but another spot showsthat the pedal isn’t applied for some reason when it is, I’ll attach a video of that if I can figure outhow.

Man this is a weird one. Must be a BCM or wiring problem. I know, that really narrows it down right? Sorry.
I looked at the sensor in the electrical body manual and it is not a simple switch like the past it is actually a real sensor so a slightly bad connection could do crazy stuff I think.

Curious what scan tool you are using, sounds like a good one.

Seems if you can command them on and off the BCM is most likely ok. Can you command them off when they are stuck on?

 

[ARCowboy]

I've had this happen on my 2005 6.6 duramax and it was the brake booster (hydro boost, whatever it's called). I'm not sure why that would happen on a truck this new but a way to check would be if you can lift the brake pedal towards yourself when you're in the driver seat and the brake lights go off/cannot shift out of park without applying it.

Otherwise it seems electrical, and my condolences.

Edit, hows the level of your power steering fluid ? Since the brake booster should share a reservoir with that.

 

[evanspears1]

The scan tool I was using was a Snap-On Solus Edge, it’s a pretty sweet outfit, unfortunately I was getting frustrated and didn’t think to check if I could command them off when they were on, I would assume I could though...

Ill check the fluid level, but I do know that pulling the pedal toward me had no affect on anything.

 

[billsite34]

It doesn't have power steering fluid, it's electric power steering.