When the nose gear is down and locked, the landing lights go into bright mode (28 volts AC instead of 24volts AC).
There is also a wing landing light heating system to help prevent thermal shock (which reduces the life of the lamps). When the nose gear is not down and locked, the airplane is in the air and landing lights are selected OFF, a small current flows through the lamps to keep them warm (in low light conditions, you can see the lamps glowing).
Rgds
NSEU