Electrical issue

In my 1996 Buick Century Wagon, when I apply brakes, the brake lights come on, as well as, the dash lights and all the running lights, front and rear. The brakes and turn signals cause the dash lights to dim and brighten. The hazard lights cause all the running lights, turn signals, and dash lights, to flash on and off in unison.

Could this be caused by a hazard switch? A brake switch?
Any thoughts?