Ok, here's a good one...

When I first purchased the car I noticed that when the normal headlight beams are on, the passenger side is very dim. At first when the high beams are turned on the passenger side headlight went completely out. I didn't take a second look at it for a couple of days, but now I notice that the high beam works, but the normal beam is still dim.

First thing I did was swap the headlights, and both are indeed in perfect working order. Next I unscrewed the ground wire and cleaned it with a wire brush. Didn't help. I used an Ohms meter and tested all three wires coming from the headlight to the plug and they were good, I also tested the plug's ground wire to the wire screwed to the frame and the ground was good... so the bulb is good and theground is good... the plugs looked good, no corosion or anything... what can I check now??

Thanks in advance for the help!