gandeboz

im not sure if my brake light switch is messed up but my brake lights only show if im putting my foot to brake pedal pretty much all the way. i feel like its dangerous if im braking lightly and my lights dont come on. any help for this

Stimeybob

I think you're right, sounds like a brake light switch to me as well.

owc6

I'm not sure if you mean the brake pedal position switch (sensor), but if so, I think this may be it. Especially if your car is a manual. If this was going bad in an auto, you would not be able to start the car.

Either way, to test if this is starting to go bad, try lifting up (pulling up) on the brake pedal with the top of your foot on the underside of the pedal and see if it behaves better when you press the brake after.

Dano523

Tech II to recalibrate the brake pedal position.

Hence brake pedal sensor works off Ohm reading feed back, and since every brake pedal sensor is slightly different, you have to do a relearn of the brake pedal sensor when it or say brake booster is replaced in the car.


As for when your doing the BPP relearn, don't go buck wild pushing the pedal past more than your normal brake pedal use position for the relearn position.
So when you start off doing the relearn, first learn will be the pedal at rest, then Tech II will tell you to push the brake pedal down so it can relearn this other brake use position (ohm feed back from the sensor). So guys will over push the pedal way, way down so the car thinks that the Ohm reading has to be this increased from the brake lights to come on, and what causes the problem with the brakes only coming on when you really get after the pedal isntead.

So again, on the pedal push during the BPP relearn, just press the brake pedal down until you just start to feel brake resistance and no more (like you just lightly using the brakes).

And like always, if you list your location, someone local may have a tech II to give you a hand to do the BPP relearn.
The dealer is going to charge you around $150 to do it, but with a tech II in in hand to do it yourself, it only takes about 3 mins.

And not, don't think that is the brake pedal sensor bad, since if the sensor was having problems, then at some point the Ohm readings from the sensor would be all screwed up, and this would end up with the car throwing codes. So at brake pedal rest, the Ohm reading form the sensor will be light, as you push the pedal, the ohm readings increase from the sensor, and its the BPP relearn that tell the car as what pedal pressure/increased ohm reading, that the brake lights should come on.

gandeboz

yes it does help but then gets messed up again after a ride.

gandeboz

contacted GM dealer and explained the symptoms and situtation and said based on what i told him, i need a brake switch and recalibration which would be $580 before taxes and to bring the car. just wow :/. honestly why does GM charge so much for small things

TxLefty

Because they can, I guess. Just to put things in perspective, saw a deal yesterday for a 7 day European vacation for $1,200 per person including airfare. Hard to compare the price of those two items and not wonder what is going on.

Dano523

The brake sensor only take about a Hour to replace, but it a PITA since you have to remove the bottom dash valance, remove the sensor, and replace the sensor while cramped in under the dash like a contortionist while you hold the U lever on the brake pedal stud as you tight the bolts.


Then comes the tech II portion, which GM style costs around $2K for the tool, then about 4K a year for a full subscription for the dealer ship. Hence why they charge about $130 when ever they need to use it, which is pretty much every repair since it used for trouble shooting the car as well.


So, since the Tech II is needed to even trouble shot when your wrenching on the car yourself, its the reason that most of use own clones of such, which cost $100 for MDI clone with cracked Tech2win software, or around $300 for cloned actual tech II instead.
https://www.corvetteforum.com/forums...ternative.html

Simply put, even if you need to change the brake pedal sensor yourself, they are only around $40, and then just need a tech II to do the BPP sensor relearn.

And again, listing your location, someone local may have their own clone to drop by and give you a hand with the needed relearn, and really think that the problem is that the BPP sensor just need to be relearned correctly to start with (light pedal pressure as the BCM learns the ohm value during the pedal push).

And again, if the sensor was bad, would get a wonky Ohm reading as it moving/changing with the pedal push, and the BCM would be sending a DTC for the erratic ohm readings through the sensor ohm movement range. Hell, with a tech II connected to the car, you can watch the ohm increase of the sensor to make sure it still working correctly to begin with (steady increasing in ohm resistance with pedal movement).

Hence on older cars, you just had a contact switch with that would disengage when you pressed on the pedal to turn the brake lights on.
The C6 brake pedal sensor is not like this, but has a base line ohm reading when you don't touch the brake pedal, then increasing ohm reading as you are pressing on the brake pedal downward (the farther you press the brake pedal down, the higher the ohm reading through the sensor). So BCM needs to learn the base line Ohm reading with you not pushing on the brake, then the pedal push point in which the ohms through the sensor increase to the point of turning the brake lights on.

So now, the BCM is set for too much brake pedal push (higher ohm reading from the sensor) before the the BCM will turn on the brake lights, and just need to reset the BCM so it turns the lights on with less of a pedal push/lower ohm reading from the sensor isntead.
Note, on automatic trans cars, it uses the same brake pedal sensor ohm reading as well before it will let the car start.

So still think that someone did something to the brakes or brake booster, the pedal is not having to travel as far down for the brakes to work, but did not do the BPP relearn for the new brake pedal position of the brake pedal when the brakes activate, and the problem at hand. Of just could be wear of the steel pedal stud to the ID of the plastic forks that is causing the lower OHM reading with pedal push, and the BPP relearn will solve this as well.