I have owned several Volvo’s. I don’t think it’s the memory switch as indicated during the show. The 850 and S70 which replaced it both have a problem with the power cable for the seat controls on the driver aside fraying and/or stretching. Erratic motor movements are usually a sign that the cable has stretched (causing poor connections @ the junction clips) or frayed, causing a short. Eventually the power controls will fail completely. Generally, a dealer or volvo technician can replace the wiring harness for the seat or simply reset the cable position if it has stretched. The last time I had this done, it costed $80. It is not a do it yourselfer, b/c the seat is very difficult to get apart, and even more difficult to get back together.