Need to post the year of the trailer and whether or not you have an old style (grease inside cover) winch or new style (no grease inside housing).
But if you have an older model (grease), you might want to pull the winch cover and check the voltage at the switch connections.
Also, check the switches. The little buttons on the limit switches that are pushed in by the plate (lower limit) or a bolt head on the plate (upper limit switch) can sometimes be jammed into the housing. If the button, on the upper limit switch, is jammed into the housing, it will not allow the winch to power the roof up.
Newer model is probably similar, but don't know for sure.