Wow, I actually have pretty damn good pictures of this!
Now, first off, I'm not saying that this is necessarily your problem. However, it is a potential reason in why your level switch isn't causing movement of the passenger side. You may not even have to take the bumper off, you might be able to get the closest bulb out, get a gloved finger in the housing and pull the internals towards the back of the housing towards the ball.
Here is the outside of the housing, with the motor circled. This is the location of the ball joint, as the motor essentially just pushes the ball in or out depending on the setting.
Now, the internals. The connector on the internal component is a yellowish clip (mine is slightly damaged in this photo, the light was salvaged from a crashed car and repaired) that snaps over the ball (circled but slightly out of focus).