Memory not functioning, pulled the seat and inspected the control. Isolated corrosion but appears to have infiltrated some traces. Does not look to me to be salvagable.
Anyone have a working one of these just lying around? I know, I know typically I'd have one or two of these collecting dust on a shelf...

Alan, thanks for the great writeups on RL search. Made it easy to source the problem.

 

Pricey dicey - best price used $350-400. New $900.
FWIW