You said that you swapped the seat control modules.
So I suspect that one that is installed in the driver's seat (which was the one that was in the passenger seat when it was not working) is bad. When you swapped them, it temporarily worked, but I would replace it.
'95 Alpine M3 LTW
'00 Dakar M Roadster
'02 Topaz M3
Red/White SRF #4 (Chassis 561)