What was found
CREW REPORTED AIR RETURN, NOSE GEAR DOORS SEEMED TO HAVE REMAINED OPEN UPON GEAR RETRACTION. LG INDICATOR SHOWED -UP- GEAR WAS CYCLED IN FLIGHT, AIRCRAFT LANDED UNEVENTFULLY. MAINTENANCE VISUALLY INSPECTED NOSE GEAR COMPARTMENT FOR LOOSE PANELS, FORWARD AVIONICS COMPARTMENT FOR SOV VENTS FAULTY AND FOUND NO DEFECTS. REMOVED AND REPLACED NR 3 UP NOSE PROXIMITY SWITCH IN NOSE LANDING GEAR COMPARTMENT IAW EMB135 MM 32-61-01, PERFORMED LANDING GEAR EXTENSION AND RETRACTION IAW EMB135 32-30-00, OPS CHECKED GOOD. AIRCRAFT RETURNED TO SERVICE.