1986 Fleetwood Brougham

Yeah try the fuse first to make sure it's not blown/corroded. Next guess would be the switch like Jared said. If neither of those are the culprit you could also start tracing wires just to make sure none are pinched or stripped/grounding out
 
Do you have access to a test light or multi-meter? You can check for power at the seat switch, if no power, probably fuse. If you have power then probably switch. oh and welcome to CGM!