What was found
DURING TRAINING FLIGHT, THE LANDING GEAR WOULD NOT EXTEND NOR THE HANDLE LIGHT ILLUMINATE WHEN GEAR DOWN WAS SELECTED. GEAR WAS EXTENDED MANUALLY AND THE AIRCRAFT MADE A NORMAL LANDING. THIS CONDITION WAS ENCOUNTERED AFTER REPEATED GEAR EXTENSION/ RETRACTION DURING TRAINING FLIGHTS. A CONTRIBUTING FACTOR MAY BE THE -30 DEGREE F TEMPERATURES ENCOUNTERED. MAINTENANCE DISCOVERED THE 60 AMP BREAKER FOR THE EXTENSION/ RETRACT MOTOR LOCATED UNDER THE FLOOR POPPED. THE CONDITION COULD NOT BE DUPLICATED IN THE HEATED HANGER. AIRCRAFT RELEASED FOR SERVICE.