What was found
BEFORE TAKEOFF, TURNED THE DEFOG VENT MOTOR ON FOR VENTILATION. AFTER TAKEOFF, CLOSED THE CABIN VENT. MIDWAY THROUGH CLOSING, SPARKS AND SMOKE COULD BE SEEN IN THE NOSE NEAR THE DEFOG VENT MOTOR. DEFOG VENT MOTOR CIRCUIT BREAKER TRIPPED AND SMOKE AND SPARKS STOPPED. FOUND THAT VENT DOOR CABLE CONTACTED THE FAN WHEN CLOSED, INSPECTED FAN MOTOR, FOUND SERVICEABLE, REPOSITIONED AND RETURNED TO SERVICE.