e430 window&seat failure

Car is a 99 E430 with 117,000 mi. Recently, 3 of the power windows failed, as did the seat adjustments and seat heater. When the battery was replaced, the problems partially resolved; the windows worked, but not well, and the seats and mirors began working. However, in a few days, all the problems returned. My mechanic replaced the window switch set, which only made the two rear windowwork. He is stumped, as am I.