have you checked each unit seperately? bypass the switch to the blower motor and run it off just the batt and so on and so forth. also follow the power off the batt to each unit with a test light. i am guessing ya have a ground problem.
sounds like bad grounds all the way around. need cleaning or replaced. frist run a hot wire form the batt to the headlight plug in see if they light up. then fix the grounds. if all else fails, chenge the headlight switch