I'd taken the seats out on my S2 Aero as one of the runners had packed up.
under the seat you will find a connection box, this is surplus to requirements and I believe is for the US market. So the plug you are looking at might not be the one you need. IIRC the wiring runs down the seat belt mount.
Removing the seat is relatively straight forward (only 4 nuts) but does require some flexibility it terms of removing the rear nuts. But this should give you a better view of what the issue is.
Don't make the mistake I did if you can use a ratchet type ring spanner otherwise you'll spend forever trying to put the seats back in.
Good Luck
