Seats on 01 clk 320 wont move forward or backward?

the problem with your seats is the "seat control module" it is located under the driver's seat and is about $250 on-line and about 2.5 hours labor to install it at the dealership. I'd suggest buying it yourself and then taking it to the dealer so they don't charge you about another $300 mark-up on the part. It's what I did with mine when the seats stopped working in my 1998 clk. Good luck. Usually there is a green colored knob on the doors that stores memories of seat positions. When this gets 'confused', it jams and the seat(s) will fail to move or just move in one direction only. One thing u could check first is the switch hidden in the door panels behind the knob that moves the seat forward/backwards on each door. Disengage it and wait a few minutes, then replug. This 'resets' the 'memory' and allows the knob function as normal. This solved the problem with mine.