As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
NR 1 (LEFT) ENGINE COWL ANTI ICE WAS SLOW TO OPEN/CLOSE. LAST ATTEMPT TO OPEN ON THE GROUND TOOK OVER 5 SECONDS WITHOUT INDICATING OPEN AS SWITCH POSITION OPEN SO WE CLOSED IT AND THEN WENT TO INDICATING CLOSED. REPLACED NR 1 ENG COWL A/I VALVE PER AMM 30 21 11 400 801.