Front Passenger Seat E270-CDI 2002 model electric

[RonSingh]

Hi Everyone this is my first time and I’m not sure I’ve posted this right. My E-class has been in my family since 2002 my late father adored it, however with age few minor issues have materialised.
My front passenger side electric seat the back won’t go back and forth.It only goes forward but not backwards can anyone help ?/