2019 -2020 Silverado turn on brake service mode to retract emergency brake piston/motors

I only figured this out on accident, I couldn't find this information anyone on the internet and everyone says you have to have a scanner to do this. I was trying to follow a different procedure from a different GM vehicle and could not get it to work and accidentally stumbled onto this method .
I know I didn't say it in the video but I started with the truck off and not in ACC or key on.

Also I am not a mechanic and do this at your own risk!!!!