Thought I would add this info also.
While in park you can press the brake pedal and hold it and as the pedal goes down due to not holding under pressure the brake light comes on.
The brake fluid leaves the master cylinder goes thru a proportioning valve then the fluid for the front goes to the calipers and the fluid for the rear goes thru a RWAL module then to rear wheel cylinders.
Since the brake light is coming on could there be something going wrong with the RWAL ? Not sure how that works or what is triggering the light to come on.
2013 Jayflight 32bhds , Outside kitchen,Bike/Cargo rack,thermal pkg,elite pkg,elec stab jacks,outside grill,pwr awning,roof ladder,hideabed sofa,technology pkg,15k btu A/C upgrade,8,367lbs dry wt
1994 Chevrolet Crew cab dually 6.5td,auto,silverado