A winch moves in and out in directions, which the tachometer can monitor on the side of the motor. To test a winch solenoid a wire is connected solenoid of the winch with the battery and will try to move from its set position when power is applied. The charging power moving from battery to solenoid is 12 volt, and if it is malfunctioning, it will make a clunk sound. This will continue for a few seconds and then stop as the current running through the solenoid drops below 3ma.