This has happened once before and eventually started working again.

When I came out this morning I hit the unlock on my remote and the drivers side headlight didnt come on. The passenger side one works fine. The running lights, turning signals, etc etc, all work correctly.

In the past when it started doing this, eventually it would come on but maybe a half a second or a full second after the passenger side one would come on.

Yes...I have replaced the bulbs.

What could be causing this?