Chevrolet Repair Questions? Ask a Chevy Mechanic for Answers ASAP
Hi my name is ***** ***** I will be happy to assist with this today.In some cases I may need more info to assist better.I apologize for any delay.
Can you tell me the engine liter size in your model here?
Are you saying the brake lights only work when shifted into reverse?
Has anything after market been installed/wired in at all?
Let me know so we can continue,thanks Pete
O.k.,this sounds like the common fault with the BCM (body control module ECU).The brake switch sends a signal to the BCM and then the BCM sends the signal out to the brake lights.When the BCM is acting up like this here it causes this issue as well as can turn on the ESC light in some cases.
What needs to be done from here is to have the fault codes read out of the BCM.This will require a scan tool plugged into your model that can communicate with the BCM to see the data signals from the BCM as well as read the fault codes to help pinpoint this as the cause here for sure.I suspect the BCM will need replaced.
The cost with labor for this can be around $500 and it has to be replaced with a new BCM as a used one is already programmed to a different model and cannot be put into another model and the new one will need programmed to your model by a GM dealer after it is installed.
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The BCM is a computer box with a circuit board and relays built into it so it cannot be cleaned and dielectric grease wont help when it fails or acts up like this here.Unfortunately it cannot be installed and then taken in for programming as the engine will not start until it is programmed so it is usually best to have it installed and programmed at the same time.
One thing you can try is to see if a local parts store can obtain one pre programmed ready to go for your model here.In some cases this can be done.
Let me know if you need anything else and feel free to rate my help here as this is how I receive credit for my time.