These Units use White-Rodgers Solenoids, Power goes thru both in forward and reverse. Normal close side on one and activated side of the other. you can not see burnt contacts inside. If it work in in one direction and not the other and you can hear or feel the solenoid close or activate, the one of them is most likely bad. directional problems tell me motor is good. bad contacts inside of the solenoid. Very Common problem.