I have a 2001 C320, the driver power seat functions fine except for forwards and backwards. Its very random, it does work sometimes but most of the time I just hear therelay clicking but the seatdoesnt move. Can someome please advise? New motor? I checked to ensure there was nothing blocking the seat.

 

1st thing make sure it is normalized. so the seat knows where the furthest stops are front to back and up and down. move seat all the way forward and hold the switch for a few seconds then do the same all the way back, up, and down in the front cushion and the back of the cushion. the headrest also, all the way up and down.and the backrest too all the way forward and back. if then it still doesnt work for you then could be a switch problem or the electronic seat adjustment module. also just make sure you are totally plugged in undetr the seat.

 

I cant get the seat to move forwards are backwards now.... Do you have the parts numbers for the switch or seat module? Can I try something else to test what is defective?

 

If the relay clicks when you operate the switch then the switch is likely OK.
Question is whether power is reaching the motor.
Need to measure voltage at motor.
IMHO motors are very robust since they are protected by use of load sensing circuitry (hence need to normalise as already suggested but loose connectors, bad relays and damaged wiring are all too common.
If all the other functions on the seat are working fine the need to determine the power at the motor connection with the switch in the correct position is the sensible way forward.
Of course you can take your car to the dealer and get them to do a "Quick Check" that will identify any diagnostics codes that will in turn point to where the circuit has a problem. This route will cost 1. for the test and 2. for the diagnosis and repair.
All depends if you are a competent DIYer in which case you may be able to save yourself the cost of the quick test.

Stuart