Brake Lights Always On?


josh_leibold
05-01-2013, 05:44 PM
Anybody who could answer my question would be extremely helpful!

--So I drive a 2008 Chevy Cobalt LT Coupe. Since last fall i have had problems with my cruise control. I am having problems because everytime i go to set it, it wont come on. I surely figured out what was wrong and figured out that it was my brake light switch. So i paid to get that replaced and sure enough i have a brand new, from the dealorship brake light switch. This was last week, now my brake lights still stay on which will not allow my cruise control to work. I took it in today and they told me everything with the cruise control and the electrics going to the brake light switch was good. However, my brake lights still remain on not allowing my cruise control to work.

Can anybody point me in the right direction to figure this problem out? I do not want to go to the dealer because like many of us know, that will be outlandishly expensive and i dont have that kind of money. I know i figured i will have to pay to get this looked at and fixed but i want to know if anyone can help me?

Any information would be great!!!

Tech II
05-01-2013, 07:20 PM
So I drive a 2008 Chevy Cobalt LT Coupe. Since last fall i have had problems with my cruise control. I am having problems because everytime i go to set it, it wont come on. I surely figured out what was wrong and figured out that it was my brake light switch.

How did you determine that it was the brake switch? Were the brake lights staying on at that time?


So i paid to get that replaced and sure enough i have a brand new, from the dealorship brake light switch.

So, who installed this and checked this out? You or another garage? Did they make sure the brake lights worked properly and that the cruise worked after installation?


This was last week, now my brake lights still stay on which will not allow my cruise control to work.

Were the brake lights staying on, immediately after the new switch was put in, or did this happen one week later.....If it happened later, was the cruise working immediately after the switch was put in?

I took it in today and they told me everything with the cruise control and the electrics going to the brake light switch was good. However, my brake lights still remain on not allowing my cruise control to work.

How is that possible?...can't they see the brake lights on? They either don't know how to fix it, or don't have a scan tool....

Can anybody point me in the right direction to figure this problem out? I do not want to go to the dealer because like many of us know, that will be outlandishly expensive and i dont have that kind of money.

Outlandish? How much did you pay thus far, and have nothing to show for it? If you went, it would be fixed by now...

I know i figured i will have to pay to get this looked at and fixed but i want to know if anyone can help me?

First off, it is a brake pedal "sensor", not a switch.....this is an input to the BCM.......depending on the position of the brake pedal, the BCM then commands the brake lights on....obviously those guys who did the work did not know what they were doing.....to diagnose this you need a scan tool capable of communicating with the BCM.....the BCM controls both the brake lights and the cruise control....

Did they even check for BCM codes?

josh_leibold
05-01-2013, 10:32 PM
I determined that it was the brake light switch because the lights would stay on all the time while driving, but not while i was in park. So i got a new part sent from Chevy and they installed it and now the brake lights are always on.

I had someone install the part and they tested it and this was last week. After i picked it up last week, i drove it 2 and a half hours with the cruise on and that was the last time it worked. And since then the lights have been on the whole time.

Cruise Control was working immediately after i got my car back with my new brake light switch in and then stopped working the next day.

Its very possible they dont have a scan tool. I am military and the place i go to is on base. So i am not sure. They said it could be the wiring but i could not get a definite answer.

If i went to a chevy dealership, they would be able to get this fixed? How much would this cost?

I do not believe they even messed with the BCM. However, i did get a full system scan last summer and i was told that there wasn't a full read in the BCM, so now that i remembered that, this could be what it is. I dont know too much about the guts of the car, so this is why i am needing some help.

What would my next step to get this fixed so my cruise control works and my brake lights work when i step on the pedal?

Tech II
05-02-2013, 09:32 AM
"I determined that it was the brake light switch because the lights would stay on all the time while driving, but not while i was in park."

Now that doesn't make sense, does it?

The lights would be out in Park, but as soon as you put it in gear, they would go on...then back in park, they would go out?

First thing to do is a scan for "B", or body codes, and also "U", or communication codes....heck, might as well go all the way and scan for ALL codes...

GMCustomerService
05-02-2013, 10:22 AM
I determined that it was the brake light switch because the lights would stay on all the time while driving, but not while i was in park. So i got a new part sent from Chevy and they installed it and now the brake lights are always on.

I had someone install the part and they tested it and this was last week. After i picked it up last week, i drove it 2 and a half hours with the cruise on and that was the last time it worked. And since then the lights have been on the whole time.

Cruise Control was working immediately after i got my car back with my new brake light switch in and then stopped working the next day.

Its very possible they dont have a scan tool. I am military and the place i go to is on base. So i am not sure. They said it could be the wiring but i could not get a definite answer.

If i went to a chevy dealership, they would be able to get this fixed? How much would this cost?

I do not believe they even messed with the BCM. However, i did get a full system scan last summer and i was told that there wasn't a full read in the BCM, so now that i remembered that, this could be what it is. I dont know too much about the guts of the car, so this is why i am needing some help.

What would my next step to get this fixed so my cruise control works and my brake lights work when i step on the pedal?

Josh_leibold,

I am sorry you are experiencing these issues with your vehicle. If you take your vehicle to the dealership you may be subject to a diagnosis fee. However, depending on your dealership your diagnosis fee will go towards the cost of the repair if you choose to have the repair done. If you would like you can private message me your name, VIN, mileage, address, and phone number so I can try to assist you in getting this concern resolved. Look forward to hearing from you.

Erica Tiffany
GM Customer Service

josh_leibold
05-02-2013, 09:37 PM
Tool II,
Yea it doesn't make since to me either. Thats why i am trying to figure out the cause so i might be able to get it fixed. I just noticed today that my brake lights just stay on. They dont turn off when in park. As soon as I start the car they come on and stay on without my foot on the brake.

Any advice on this?

gmtech1
05-03-2013, 11:45 AM
Disconnect both large connectors at the BCM, apply a LIGHT coat of dielectric grease to the plug side of the harness, so the terminals get coated when reinstalled. I have seen this several times and the plug thing fixes it every time. It has what GM calls "terminal fretting".

Tech II
05-03-2013, 04:23 PM
GMTech1.....possible, but I think his BCM has gone south...and it's not even winter....

josh_leibold
05-06-2013, 07:41 AM
So I'm gonna have to get a new BCM?

gmtech1
05-06-2013, 09:39 AM
So I'm gonna have to get a new BCM?

Did you try what I suggested with the plugs? It only takes about 5 min to do. If the lights are fixed after that, you're done.

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