A diagram of the headlights really will not help you all that much. You have something wrong with your charging system. Most often this is a failure of one or more of the diodes in the rectifier that will cause fluctuating voltages that you will see as flickering lights.

I know on some of the GM passenger cars, this has been traced back to a corroding ground inside the alternator. Crappy part is that some of the remanufacturers are not cleaning this area and new units cause the exact same symptoms. This can cause a battery to go bad due to over charging as well.

 

everything always leads back to that alternator lol. i'm on my 4th alternator right now. this latest one is from dbelectrical. would that explain why all the lights flicker more when its cold out? some ppl tell me its a loose connection but idk. could the distro block under the battery have anything to do with it?