What was found
(CAN) DURING TAXI, NR 2 AIR CONDITIONING SYSTEM BECAME NOISY AND PRODUCING SMOKE AND ODOUR IN THE CABIN. NR 2 PACK WAS SHUT DOWN. EMERGENCY EVACUATION WAS EXECUTED DUE TO SMOKE AND ODOUR STILL COMING FROM NR 2 PACK AFTER SHUT DOWN. DURING INVESTIGATION FOUND THAT NR 2 PACK CONTROL VALVE CIRCUIT BREAKER HAD TRIPPED. DURING TROUBLE SHOOTING, IT WAS CONFIRMED THAT THE ACM OVERTEMP SWITCH WAS SHORTED AND CAUSING C/B TO TRIP FOR NR 2 PACK VALVE. OVERTEMP SWITCH WAS REPLACED AND SYSTEM TESTED SERVICEABLE AS PER MAINTENANCE MANUAL.