What was found
(CAN) AFTER TAKEOFF WHEN LANDING GEAR LEVER SELECTED UP, THE LANDING GEAR DID NOT RETRACT AND THEY HAD 3 RED AND 3 GREEN LIGHTS. THE HANDLE WAS SELECTED BACK DOWN AND THE RED LIGHTS EXTINGUISHED LEAVING 3 GREEN DOWN AND LOCKED LIGHTS. CREW RETURNED ACFT TO DEPARTURE AIRPORT. MAINTENANCE CARRIED OUT FIM TASK 32-30, TASK 815 WAS C/O AND THE MANUAL EXTENSION DOOR SWITCH WAS FOUND DIRTY, SWITCH WAS CLEANED IAW AMM 32-34-00. GEAR SWINGS WERE CARRIED OUT WITH NO FAULTS FOUND. THERE IS A KNOWN ISSUE WITH THE SWITCH, SB 32-1443 IS CURRENTLY BEING CARRIED OUT ON OUR FLEET TO REPLACE SWITCH WITH A NEW AND IMPROVED SWITCH. HOWEVER THIS ACFT IS STILL AWAITING THE SB TO BE CARRIED OUT.