2000 Blazer Drivers window

my 2000 blazer drivers window, periodically works. When it does, everything is fine. When it doesn't you can hear a clicking/ratcheting sound in the door panel. Any ideas, or what I need to do?

this worked for me. my brother (my mechanic) took the door panel off and he had found that the rivets that hold the motor to the door were loose. loose from the window motor. he re-riveted the motor (creating a good ground) and never had the problem again. hope this gets you thru the drive in bank tellers and burger joints.......good luck