how to repair seat adjustment on mecedes slk230

Slide your seat to back. Unscrew 2 glide screws I think with hex and then you have seat released and easy access to electronics

Of course if it's the backward and forward slide thats not working you'll find that near impossible. It's highly unlikely that it'll be a problem with the motors, i've never heard of them breaking down. Likelyhood is it'll be the switch itself, a fuse or a relay. If you've got the owners manual check the section on the fuse boxes, should tell you which fuses and relays control the seats, if that gets you no joy then start looking at the switches.