What was found
A/C NOT PRESS. RT PACK PRESSURE INDICATED ZERO AND LT PACK TRIP LT ILLUM AND TRIPPED. FLT RETURNED, LANDED W/O INCIDENT. NO EMERG WAS DECLARED. MAINT FOUND LEFT PACK TEMP SENSOR BAD. R / R LT PACK TEMP SENSOR. REP P5-10 AC PANEL DUE TO LT PACK SWITCH INOP. OPS CK GOOD. RT ENG BLEED AIR REG INOP. R / R RT ENG BLEED AIR REG. R / R RT BLEED AIR CIRCUIT BREAKER FOR TRIPPING. OPS CK GOOD. PROBLEM, RT PACK PRESSURE INDICATING ZERO, RT BLEED AIR CIRCUIT BREAKER TRIPPED, REPEATED. MAINT R / R RT M1455 AC ACCY UNIT ON E2-3 SHELF IN E / E COMPT, R / R ENG FIRE CONT PANEL, CONNECTOR D3304 AT RT ENG DISCONNECT BRACKET AND REPAIRED WIRES. OPS CK GOOD.