Wis. Admin. Code Trans 305.075
Auxiliary lamps
Cite as Wis. Admin. Code Trans § 305.075
Auxiliary lamps.
(1) Auxiliary lamps that are fog lamps or adverse weather lamps may not be used in lieu of headlamps during those times when headlamps are required except as expressly allowed by s. 347.26 (3) , Stats. Other auxiliary lamps may not be used in lieu of headlamps.
(2) Unless specifically permitted by this chapter or by ch. 347 , Stats., no motor vehicle may be operated upon a highway with a lighted auxiliary lamp unless the auxiliary lamp:
(a) Is mounted below the level of the center of the headlamps, except that when added equipment, such as a snow plow, blocks the transmission of light from factory installed headlights, alternate headlights may be mounted above the factory installed headlights and may temporarily be used during the time the light obstructing equipment is in place.
(b) Directs light forward of the vehicle.
(c) Every auxiliary lamp shall be properly aimed so as to conform with manufacturers recommendations, and so that glaring light rays from the auxiliary lamp are not directed into the eyes of an approaching driver.
(d) Meets the photometric specifications in SAE technical reports J581, J582 and J583 for auxiliary driving lamps, auxiliary low beam lamps or front fog lamps.
(3) Whenever the operator of a vehicle equipped with auxiliary lamps projecting a beam beyond that of the vehicle’s low beam headlamps approaches an oncoming vehicle within 500 feet, or approaches or follows another vehicle within 500 feet, the operator shall extinguish the auxiliary lamps in order to prevent glaring rays being directed into the eyes of the operator of another vehicle.
(4) Adverse weather lamps shall be mounted below a horizontal line between the centers of the headlamps. If equipped with 2 adverse weather lamps, they shall be mounted on the same horizontal plane and on opposite sides of the center of the vehicle.
(5) Motor vehicles may be equipped with auxiliary off-road lamps that may face to the front or rear of the vehicle. The lamps shall be wired independently of all other lighting circuits and may not be lighted when the vehicle is operated or driven upon a highway.