singled4d

Hi everyone I have a 2002 C Class Evolution 220 CDI, My passenger headrest was broke by my son being rough with the seat the other day. Basically he threw the seat forward and the head rest became lodged between the windscreen an the edge of the roof lining as the head rest didn't have a chance to retract itself. The only way to get the seat lowered and locked back down so I could use the car was to force it back carefully. The head rest now retracts fully when the seat is put forward like it should but has only a 1/4 of its orignal movement available when using the door switch / memory function. I've taken the back panel of the seat and every thing seems fine. I've also disconected the plug out of the motor when the seat is forward with the headrest retracted then locked the seat back down and plugged it back in, the headrest will then move all the way up but not down again unless it rises above 3/4's of the way. Really confused about it all but it was all fine before the impact my son put it through. Is there any way to reset the headrest movement or is part of the motor electrics sound shot.