Legally, I could get by with no lights on the trailer, but I don't want someone to not see the trailer at night and hit it.
Legally, you have to have lights on it.
169.50 Rear lamps.
Subdivision 1. Requirements; exception. (a) Every
motor vehicle and every vehicle that is being drawn at the end
of a train of vehicles must be equipped with at least one
taillamp, exhibiting a red light plainly visible from a distance
of 500 feet to the rear.
And if the trailer has a gross weight exceeding 3000 lbs or greater, you're supposed to have brakes on it, too.
While you may get away with not having lights on the trailer in MN , I guarantee you won't get through WY at night without having lights on the trailer.
My neighbor got stopped for not having lights on a Bobcat trailer, and THEN ALSO got a ticket for no brakes. He didn't have the proper connector on his Suburban and they made him park it and I had to go pull it home for him.