As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON ARRIVAL INTO SEA 15000' WING ANTI ICE WAS SWITCHED ON L VALVE CAUTION LIGHT INDICATED VALVE WAS STUCK CLOSED. GROUNDED - YES. VERIFIED VALVE NOT OPENING, REMOVED & REPLACED L/H WING A/I VALVE REFB737-9 AMM 30-11-11 OPS & LK CK GOOD.