2000 Focus Headlights

Problem with my headlights dimming and getting brighter and dimming. I am thinking this problem goes along with my blower motor slowing and speeding up back and forth. Would there be a bad connection somewhere that I have not found yet??

A bad ground. Dim lights and intermittent fan speed is almost 100% a bad grouind. Run a lead from a DVOM between the negative battery post and the body of the car. On the Ohm scale there should be no change or just a couple of ohms difference. If it is more than this you need to run a cable between the car body and the engine block.