Sounds like you've got a series wound motor with separate terminals for
the field and armature. If my memory is correct the polarity of the
armature winding gets reversed to change rotation.

It looks like your switching modules are working OK which will save you
some money. Otherwise I'd suggest an anchor windlass controller such
as an IMTRA. They occassionally show up on EBAY at halfway reasonable
prices. Be sure you get one designed for a series wound (4 terminal)
motor.