What was found
HAD ANTI-ICE MASTER CAUTION ON TAKE OFF ROLL N1 91.4, 28K ENGINE ANTI-ICE ON. GROUNDED - YES. PERFORMED ENGINE HIGH POWER RUN TAXI PER B737-9 AMM 71-00-00 DURING TAXI COWL VALVE LIGHT ON #1 ENG ILLUMINATED 3 TIMES TO 3 FROM RUN UP PAD DURING HIGH POWER RUN #1 ENGINE AT 94 N1 COWL ANTI ICE LIGHT ILLUMINATED TWICE. REMOVED AND REPLACED #1 ENGINE A/I VALVE REF AMM 30-21-11 COMPLETED UP TO STEP 3. PERFORMED ENGINE ANTI ICE SYSTEM OPS TEST REF AMM 30-21-00-710-801 STEPSD-E 1 6S. PERFORMED HIGH POWER RUN OF A/C WITH ANTI ICE FOR 5 MIN. NO DISCREPANCIES NOTED. COMPLETED #1 ENGINE ANTI ICE SYSTEM OPS TEST REF AMM 30-21-00-710-801 STEPS E(7-10) F. COMPLETED STEP I OF 30-21-11-400-801.