What was found
PACK MODE L EICAS. COULD SMELL ACRID ODOR AND HEAT. 4 MIN LATER RECEIVED EICAS MESSGAE. APPLED MEL 2152S, CONDITIONAL INSPECTION TASK 05-51-58-800-801-C3. NO ODOR FOUND DURING THE CHECK. MEL PROCEDURE ACCOMPLISHED IAW MEL 2152S. PERFORMED FIM 21-52 TASK 818. INSPECTED LEFT PACK RAM AIR AND HEAT EXHANGER INLETS, NO BLOCKAGE FOUND. ACM TORQUE CHECK FOUND WITHIN LIMITS. PERFORMED CABIN TEMP CONTROL SYSTEM TEST, NO ACTIVE MESSAGE. FOUND ACTIVE MX MESSAGE 21-12141. REMOVED AND REPLACED RELAY K24301 REF FIM 21-27 TASK 890. PERFORMED MAT TEST ECS SYSTEM TEST, PASSED. OPERATED LEFT PACK OFF AND ON FOR APPROXIMATELY 2 HOURS AND PERFORMED NR 1 ENGINE IDLE RUN. OBSERVED NO ABNORMAL ODORS.