check the switch, it comes out real easy. it's jusr pushed in and held with
a couple of pastic tabs. becarful not to snap them, you need them.
sounds like the connector is loose. you might be able to just push it in
from underneath. if you put the seat all the way back, and lay on the
floor with your head by the brake pedal, and reach in there you should be
able to feel a connector on the back of the dimmer. it has a lock tab on
it also. try  wiggling it, then push it in and see if it seats.
or it could be the dash ground lug is loose. I'm not sure where that is,
but all the wires run through the same area. I had a simiaiar problem with
the factory fog lights, the connector wasn't pushed in all the way.