As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SEA - ON FLIGHT 2338 DURING DESCENT IN ICING CONDITIONS "DEICE PRESS CAUTION" ILLUMINATED. WHEN SYSTEM WAS REENGAGED DURING EA CHECKLIST DEICE CAUTION LIGHT EXTINGUISHED BUT BOOTS DID NOT CYCLE IN AUTO MODE. LIGHTS AND BOOTS FUNCTIONED IN MANUAL MODE ONLY, DEICE PRESS WAS NORMAL THROUGHOUT. MAINTENANCE REMOVED AND REPLACED TIMER AND MONITOR UNIT. FUNCTIONAL TEST GOOD. DEICE PRESSURE CAUTION LIGHT DID NOT ILLUMINATE. AIRCRAFT RETURNED TO SERVICE.