The driver may operate the vehicle with the snow plow headlights on but the marker and tail lamps off, reducing the vehicle's visibility and increasing the risk of a crash.
The snow plow headlights can be turned on without other exterior lights, and high beam indicator will not work when the snow plow high beams are on. As such, these vehicles fail to comply with the requirements of Federal Motor Vehicle Safety Standard (FMVSS) number 108, "Lamps, Reflective Devices, and Associated Equipment."
What to do: Book it in at your next service. There is no deadline and no charge.