Well, if you have the same set-up as me, there is 2 additional switches on the throttle, one for forward and one for reverse. Should be easy to measure if there is contact using a multi-meter. Or bypass the "reverse" switch and see if that solves the problem, then the solution is to change or repair the switch rather than replacing the rheostat. As for the problems on my boat. Now cautiously optimistic that the clouds will part and the sun will shine again: The Duffy factory and their Service Department tested my controller and found it working, but not to the Duffy specs, so they re-programmed it and tested the system for 45 minutes, now it works good and should last a long time. We shall see after UPS delivers the package Monday.