What was found
(CAN) LANDING GEAR FAILED TO EXTEND WHEN SELECTED. APPROXIMATELY 1-5 MINUTES GEAR EXTENDING WITH NO ADDITIONAL CREW ACTIONS. AIRCRAFT RETURNED TO MAINTENANCE BASE. AIRCRAFT EXPOSED TO -30 DEGREES COLD SOAK FOR APPROXIMATELY 3 HOURS. AIRCRAFT PREVIOUS OPERATED IN WARM CLIMATES FOR 20 YEARS. MAINTENANCE FOUND VERY DIRTY AND (GUMMED) SWITCHES IN LANDING GEAR CONTROL HANDLE. FIRST EXPOSURE TO COLD CONDITIONS SINCE IMPORT.