What was found
PILOTS REPORTED THAT A DUCT OVERHEAT LIGHT ON THE LT SIDE ILLUMINTATED. DURING POST MX ENGINE RUNS, MX HAD NOTICED A BURNING SMELL COMING FROM THE LT PACK. MX ORIGINALLY PLACED THE ISSUE ON MEL 21-50-2 CAT.C, HOWEVER, ULTIMATELY MX R & R THE LT AIR CYCLE MACHINE PN OFF 2204540-4 SN OFF 38-345 IAW MM 21-50-05 OPS CHECK IAW MM 21-50-00. NO SMOKE SMELL NOTED AND THE OPS AND LEAK CHECK WERE GOOD. ADDITIONALLY MX TROUBLESHOT THE PACK SYS AND FOUND THE LT GROUND COOLING FAN TO BE INTERMITTENT. MX R & R THE LT GROUND COOLING FAN REF MM 21-52-03. PN OFF EVAC2322C2 SN OFF 336 ALL CHECKS WERE GOOD.