I'm interested in tracking down a rattle in my passenger seat belt retractor. The noise sounds like a mechanical relay repeatedly firing - best picture I can paint to describe it is imagine shaking a ball bearing rapidly from side to side in a matchbox. Anyway, it's got to have something to do with the electrical monitoring of the seat belt mechanism because the sound ONLY occurs when there is a passenger in the seat, and ONLY when the belt is fastened. My understanding is that there are sensors monitoring both of these conditions. When I sit belted in the seat with my wife driving (good idea by the way...), I hear the noise. If I unlatch the belt but continue to hold it tight around me, the simple act of unlatching the belt makes the noise stop immediately. If I drive around with the belt latched and the seat empty - no noise. The noise seems more related to inertia (another clue that it's related to the retractor locking somehow) rather than road bumps per se. The noise will still occur on a perfectly flat smooth road. Stealership tells me I would need to replace the entire belt mechanism to stop the noise. Go figure. Anybody with any mechanical know-how about how the interior mechanism actually works got any suggestions on how to troubleshoot? Thanks!