My driver's side low-beam headlight is more dim than the passenger's side, and I've replaced the bulb twice with the same lamp, and the same problem arises? Is it a wiring problem? If so, where may it be?

 

The best place to start is under the hood on top of the cor support. There are a group of wires comming from the head lights to a bolt with a star washer. Find that it is the grounds for the head lamps. Make shure that you have a good clean connection. If not you can have a host of problems. Most of the time the loss of the ground is the culpret.

 

Going along with the last post. Another place to check would be the contacts at the light. If the molex ends are oxidized then that will also do it, just at the lights end not at the grounding points. One if not both is probably your problem