I believe the fuses for the seat heaters are 15A, and there is only one fuse for both seats in the passenger footwell, or could be the drivers, been a while since i checked.
So if the drivers is working and not the passengers then it would be more to do with the element that the fuse.
I have the wiring diagram for the heated seats, cen email it to you if you like. PM your email address.
Lee