MILT

MY firebird headlight motors do not work. The lights turn on and off, but motors do not go up/down. I replaced the headlight switch with a spare I had to no avail. Is there some sort of fuse or relay that may be bad, or is it most likely a bad ground wire? BTW, it occured when I turned the headlights up accidentally while driving, and when I tried to make them go down w/ the switch, nothing happened.
So, since both sides are affected, I am assuming the motors are fine but there must be a bad ground or relay or something. Where are the grounds for the lights located (BTW car is '87 firebird), and how do I trace this kinda stuff?

Thanks for any and all help...

MILT