Hey E, I don't have an answer unfortunitally, I was actually looking to see if you got anywhere with this. My (82 300sd) has the same problem.Back of the seat work's but not the cushion. A friend tells me he also had this happen to him once .He says that the cables that run from the motor to the gears were the problem and if tension were put on them(the cables)via pulling on them, they would opperate.Unfortunatelly this didn't work for me but if you allready have the seat out it might be something to try.Please post if you get it worked out.