More than likely due to everything they have replaced, it may be a wiring issue. However, they need to monitor the voltage at the brake switch while this is happening. Also they need to hook up the scan tool and monitor the brake pedal position sensor while this is happening to see if the pedal position sensor is activating them. I suspect it will not which means there is most likely a shorted wire that is causing the brake lights to come on.
Clearly this is a guess based on what you provided but it would be my next step.
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Monday, December 2nd, 2019 AT 7:01 PM