As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SEA FLIGHT NR 2488: DEICER TIMER AND DEICE CAUTION WILL NOT EXTINGUISH. AIRCRAFT RETURNED TO BLOCK. MAINTENANCE REMOVED AND REPLACED THE TIMER AND MONITOR UNIT IAW Q400 MM 30-11-01 PGS 401-405. OPS CHECK GOOD. NO OTHER DEFECTS NOTED. AIRCRAFT RETURNED TO SERVICE.