i have spent the last two days replacing a new motor on a single step electric kwickee step, the motor works fine using a battery in both directions but when it is wired to the existing wiring it will...
what was the reason for changing the motor did the old one do the same thing if yes, then it is a switch problem or controller problem ? IF no, the motor is wired backwards
shut off power, pull fuse , disconnect battery try swapping the two power wires to the motor
this assumes all you did was install a new motor, did not change controller the motor is wired backward