Window Motor/Snowblower and 12v only one way

[cusack80]

We have tried both motors both ways. We are running off a talon. It works great one way and stutters the other direction. When we check voltage 12v working going up and hardly anything going down. When we reverse our pos and neg on motor the problem reverses. If we hardwire (mentor does this) to battery it runs both directions fine. We go back and wire it back to the talon problem reappears and one direction works flawless other direction stutters like it is not getting power....this is for our elevator mechanism. We have tried switching PWM cable, window motor and snow blower motor and tried victor or talon and problem replicates. Any ideas?