Ok, I did remove the bumper cover, and the headlamps. I installed new bulbs on both sides. The problem still exists. Next I'm going to swap the ballast from side to side to see if the ballast moves with the change.

Does anyone have a picture and location of the leveling sensor?

My X5 was bumped on the drivers side a few months ago, but I don't drive it much at night, and don't remember if the light problem was present before the bump. Today after turning the headlight switch on, and off, the drivers side did illuminate until I turned the key off, and back on. This makes me thing the sensor is the issue.