Glad you found a solution, and hope you got your money back on the bad Maximizers. Here is the one I made, a $13 PWM module from ebay and a plastic box from Walmart. One set of wires goes to the breaker+battery, the other go to the TM.
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It is best to bypass any speed control circuit in the trolling motor, and connect the controller directly to the (fat) power wires going down to the motor. I assume that is what you are saying about the power drive, not sure I understand what you wrote.