REPLACED UPPER BLOWER WHICH WASN'T THE NOISY ONE, THEN REALIZED MY KITCHEN AID COMBO MICRO-CONVECTION OVEN HAD A LONGER LOWER BLOWER. REPLACED THAT ONE, WHICH WAS THE NOISY ONE. NOW MY THERMAL OVERLOAD PROTECTOR HAS FAILED AFTER A SELF-CLEAN CYCLE! WHILE THE UNIT WAS OUT, I CLEANED THE SMALL SPACES WHERE THE BLOWERS VENT TO THE FRONT. NOT AN EASY TASK. I TOOK A PIECE OF WIRE WITH A RAG AND SIMPLE GREEN TO CLEAN OUT THE DIRT CHUNKS AND GREASE. BE CAREFUL OF THE LATCH WIRING! ALSO CHANGED THE MICRO LIGHT BULB. BAD DESIGN, AS YOU HAVE TO TEAR INTO ALOT OF REMOVAL OF HARDWARE TO GET TO THE BULB!