Take off the switch... then bridge the connections at the plug if it still doesn't go its probably a wire to a motor inside the seat... they move back and forth over years and tend to wear and break with age.

__________________
-Marty

1986 300E 220,000 miles+ transmission impossible
(Now waiting under a bridge in order to become one)

Reading your M103 duty cycle:
http://www.peachparts.com/shopforum/831799-post13.html
http://www.peachparts.com/shopforum/831807-post14.html