2015 Chevy Tahoe engine won't start

I have a 2015 Chevy Tahoe that each week, the engine will not start.  When I

get near the car with my keys all of the service warnings come on and all of the

gauges go to the left.  The break pedal is very tight and I can't even press it

down. I think every light warning comes on like the engine, tire pressure, etc.  

This happens each week and I get stranded until it decides to start which it

actually does without me even trying it.  I will be just sitting in the car waiting

for it to start and it just does without me pushing the button and stepping on

the brake.  Also, now the driver's power seat and the power mirrors do not

work anymore.  The heated seat does work.  I have seen over $1500 to get it

fixed but no one can figure it out.  I had one mechanic clean some things on it

and the other one clean some corrosion off the sensors in the rear bumper.  

Does anyone know how to fix this?