What was found
AFTER BLOCK OUT FWD EQPT OVHT EICAS MSG. AFTER QRH CHECKLIST ACCOMPLISHED, MSG STAYED EXTINGUISHED. T/S FIM 2158 FAULT TREE 999 FOUND VALVE ASSY AIR MODULATION INOP. REMOVED AND REPLACED VALVE ASSY AIR MODULATION IAW AMM 21-58-07. OPS TESTED OK. BOTH PACKS RUNNING ON GRD ALL TIME. PERFORMED FIM 21-58 TFT 986. VERIFIED V90 VALVE MOVED TO POS C-B IN OVRD & A-B IN AUTO. AFTER 30 SEC LIGHT STAYED ON STBY. REMOVED AND REPLACED M867 CARD COOLING IAW AMM 21-58-24. PERFORMED EQPT COOLING OPERATIONAL CHECK IAW AMM 21-58-00. SYSTEM CHECKED GOOD.