If the problem is only in the drivers side headlamp, then you have a problem which is local only to that headlight circuit, because the fuse (or relay) for that circuit is in the same circuit as the passenger side light. Look for a connection problem at the headlamp itself. Usually, the circuit wires for the headlamps just loop directly from one headlamp to the other and first begins at the fuse or relay. In your case, if it loops first from passenger side then to driver side, you may want to check where it leaves the passenger side to be sure it follows through correctly to the drivers side.