What was found
AMBER TAI IS INDICATED ON THE NR 1 ENGINE UPPER DISPLAY, N1 WHEN NR 1 ENGINE ANTI-ICE SWITCH IS TURNED ON. ENGINE BLUE LIGHT COWL VALVE OPEN INDICATES BRIGHT THEN DIM WHEN ANTI-ICE SWITCH IS TURNED ON. ACFT GROUNDED. PERFORMED NR 1 ENGINE COWL TAI VALVE TEST IAW AMM 30-21-11. VERIFIED AMBER TAI ON DISPLAY. IAW WD SSM 31-62-14 PG 107, REMOVED DP1303 AND INSPECTED SAME AND JUMPED PIN 5 & 6 WITH NR 1 ENGINE ANTI-ICE SWITCH ON, GREEN TAI IS IN VIEW. RETURNED DP1303 TO NORMAL. REMOVED AND REPLACED THE NR 1 ENGINE TAI VALVE. LEAK CHECKED GOOD, OPS CHECKED GOOD, IAW AMM 30-21-11-400-801.