What was found
AIRCRAFT WAS INDUCTED INTO SCHEDULED MAINTENANCE AT LOCAL FBO. DISCOVERED FORWARD A/C BLOWER LOW SPEED WAS NOT FUNCTIONING. FOUND BLOWER CONTROLLER WAS NOT OPERATING. PRIOR TO REPLACEMENT OF BLOWER CONTROLLER, CIRCUIT WIRING WAS CHECKED AND ARCING WAS DISCOVERED BETWEEN A TERMINAL OF THE 7 1/2 AMP CIRCUIT BREAKER FOR THE LOW SPEED CIRCUIT AND STRUCTURE. THE PHENOLIC INSULATOR BETWEEN THE TERMINAL OF THE BREAKER AND THE AIRCRAFT STRUCTURE WAS MISSING. THE CIRCUIT BREAKER DID NOT SHOW A MECHANICAL TRIP BUT CONNECTION INSIDE SHOWED AN OPEN CIRCUIT.