Passenger power seat motor replacement

I am a new owner of a 1990 535i and want to replace the power seat motor. it is not working. i v checked the connections to the buttons and they are connected. where can i find out the procedure to do it?and also the cost of the motor itself?
chaz

seat motor failures are rare, cable, bowden tube and the seatback drive problems are most common...what part of the seat isn.t working????

seat motor failures are rare, cable, bowden tube and the seatback drive problems are most common...what part of the seat isn.t working????
The right side or but stays down, i noticed some grease on the motor housing and surrounding area. oh i checked the fuse and it seems to be fine.....there are some loose connections under the seat as well like abbandoned or not used plugs?

okay, closer now, is the right SEAT BACK the problem or the SEAT BOTTOM ? ?

okay, closer now, is the right SEAT BACK the problem or the SEAT BOTTOM ? ?

the bottom one side is lower then the other,

sorry but if I'm to help you here with a cable or drive repair I need to know the EXACT PORTION of the seat thats not funtional.....{r/f seat, left rear bottom, up/down or r/f seat, right side of seat back, fore/aft].etc..........