What was found
(CAN) IN CRUISE, FLIGHT CREW STARTED TO SMELL SMOKE AND OBSERVED ARCING NEAR THE NOSEWHEEL STEERING SWITCH. CREW DONNED THEIR OXYGEN MASKS, DECLARED AN EMERGENCY AND DIVERTED TO A NEARBY AIRPORT. SHORTLY AFTER CIRCUIT BREAKER 4-C1 INST FLOOD LTG POPPED AND SMOKE DISSIPATED. AIRCRAFT LANDED WITHOUT FURTHER INCIDENT. UPON ARRIVAL THE AIRCRAFT WAS REMOVED FROM SERVICE AND LOCAL MAINTENANCE QUICKLY DETERMINED SMOKE/ARCING ORIGINATED FROM FLOOD LIGHT ASSEMBLY DS3LA LOCATED JUST ABOVE THE NOSEWHEEL STEERING SWITCH. THE LIGHTING SYSTEM WAS DEACTIVATED AND DEFERRED IN ACCORDANCE WITH MEL 33-11-01-1. THE ASSEMBLY WAS LATER REPLACED AND TESTED SERVICEABLE.