What was found
LEFT PACK LIGHT ILLUM AFTER LANDING. RAN QRC & LIGHT STILL ON. LT PACK LIGHT COMES ON WHEN LT PACK IS RUNNING. LT PACK LIGHT EXTINGUISHED, ECS PACK LITE IS OFF WHEN SWITCH IS OFF, RESET PACK LIGHT & RAN LT PACK, WHILE RUNNING, BURNING ODOR IN FLT DECK, 5 MINS AFTER START, LT PACK SHUTDOWN & LT PACK LIGHT BACK. MEL 2151AM, ACFT OOS. RAN LT PACK & SMOKE FILLED CABIN. LT PACK OFF & LIGHT ILUMINATED. INSPECTED HEAT EXCHANGER THROUGH PLENUM-DIFFUSER ACCESS PANELS & NO DEBRIS. LT PACK NOT INTAKING AIR OR BLOWING AIR THROUGH EXHAUST, SUSPECTED BAD ACM. FOUND LT PACK SEIZED. REMOVED LT PACK, IAW AMM 21-51-04. INSTALLED LT ACM IAW AMM 21-51-04-400-801. OPS TEST PASSED, NO LEAKS. ACFT OK TO CONTINUE.