When I was putting on the new knob for the wiper switch, I had to hit it with the palm of my hand and doing so caused the back of the wiper switch (the black part) to come off or it broke off. I don't know how to tell if it's broken or if it just fell off. Does anyone know how they go back together, I think I found all of the parts that fell off of it. Also does anyone know how the light switch mounts behind the dash?? Thanks.