As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON DESCENT ANTI-ICE (ENG) WAS TURNED ON. NR 1 ENG TAI LITE CAME ON GREEN FOR 30 SECONDS THEN WENT OFF FOR 5 SECONDS AND CAME BACK ON YELLOW. BLUE LITE WAS DIM BLUE. GROUNDED - YES. REMOVED AND REPLACED NR 1 ENGINE COWL TAI VALVE IAW AMM 30-21-11. OPS CHECK GOOD.