Re: brake position sensor
If the brake lights ( in the rear of the car) are on but your foot is not on the brake pedal, most likely the BCM 'thinks' the pedal is depressed when it isn't. The brake pedal position sensor is not a simple on/off switch like the good old days. The sensor is also most likely not the problem. Fretting corrosion on the BCM connectors will change the voltage the BCM 'sees' from the BPPS and will change the actual counts as seen on a scan tool in BCM data. The fix is to work the BCM connectors a few times to clean off the fretting corrosion and the problem will go away for a while. You can do that yourself easily by disconnecting the battery with the key off and disconnecting the BCM connectors with the blue lock lever and disconnect and reconnect the conectors a few times. Don't side load the connectors. You could also use a product like deoxit but you would need the cleaner 'D series' and the protector 'gold series' to make a lasting repair. Then the BPPS learn should be done to zero the sensor and your lights should work properly again.
Now if the ABS and traction control lights are on, that's a different story, then a bad hub bearing could easily be the cause. Through no fault of your own, you may have been given bad info from the tech working on the car. For us to help you, we need accurate info, we can't see what you see, nor can we access the codes in your vehicle. Though you may be frustrated with the tech working on your car, that tech isn't us, go see his manager and voice your concerns with him so it has a chance of being addressed before it happens to more customers.