I'm sure this is on the forum somewhere, but I can't seem to find it. Anyway, I have a 1996 S600 and the rear sunshade is stuck in the down position. When I hit the switch, you can hear it making noise as if it is going up, then stops. Then when you hit the switch to go down, you can hear it retract. Has anyone had this problem? Is there something back there it can get stuck on?