As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SEA- ON FLIGHT 2384 DEICE PRESSURE CAUTION LIGHT ILLUMINATED AFTER SELECTING DEICE BOOTS TO SLOW. ACCOMPLISHED DEICE PRESSURE CHECKLIST. INBOARD BOOT OF HORIZONTAL STABILIZER SHOWS NOT INFLATING. DEICE PRESSURE FOR BOTH SIDES SHOWED NO DROP. BOOT DID NOT WORK IN MANUAL AS WELL. REMOVED AND REPLACED DISTRIBUTION VALVE. OPEATIONAL CHECKS GOOD. AIRCRAFT RETURNED TO SERVICE.