OK, 1st test the motor.
Get a set of jumper leads.
Leave the earth lead atttached to the housing of the winch motor and -ve on the battery.
Picture the winch motor as above with A, B, C the poles (3 positives) or bolts.
Get the 1st jumper lead and go from the left hand pole (A) coming out of the motor and the other end to the top of the two poles (B) at the drive end of the motor.
Then attach the 2nd jumper lead to the +ve battery and touch the bottom of the two poles (C) on the drive side of the motor. The motor should go, and due to the current they pull it will give a spark.
That will run one way and to test the motor other way swop B & C over. Put lead between A & C and Get Battery power to B.
Hope this helps. If that works then it is a solinoid issue.
NJ