Wis. Stat. § 347.22: Lamps on farm tractors, self-propelled implements of husbandry, and lightweight utility vehicles.

(1) No person shall operate or park a farm tractor, self-propelled implement of husbandry, or lightweight utility vehicle, as defined in s. 346.94 (21) (a) 2., upon a highway during hours of darkness unless such tractor, implement of husbandry, or lightweight utility vehicle carries the lighted headlamps and tail lamps which would be required of other motor vehicles under similar circumstances.

(2) Except as provided in s. 347.25 (2g), no person shall operate or park a farm tractor, self-propelled implement of husbandry, or lightweight utility vehicle, as defined in s. 346.94 (21) (a) 2., upon a highway during hours of darkness with any lamp thereon showing any light to the rear other than red or amber in color.