What was found
#1 ENG SELECTED ENGINE ANTI ICE ON- HOWEVER YELLOW TAI ILLUMINATED NEXT TO #1 ENG N1 GAUGE AND BLUE COWL VALVE OPEN LIGHT STAYED ON BRIGHT. LANDING WT 150,100 LBS RATE OF DECENT LESS THAN 200' FEET PER MINUTE. GROUNDED - YES. REMOVED AND REPLACED #1 ENGINE COL TAI VALVE, LEAK AND OPS CHECK GOOD. REF B737-900 AMM 30-21-11. OPENED, COLLARD, RESET 2 CB'S P18-3 ROW A COL 6,7. BONDING CHECK GOOD. PERFORMED OVERWEIGHT LANDING INSPECTION. REF AMM 05-51-35. MAX LANDING WEIGHT WITHIN LIMITS. NO DEFECTS NOTED.