As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SEA - ON FLIGHT 2167, RETURNED TO FIELD AT ABOUT 1000 FEET ALTITUDE THE SMOKE WARNING LIGHT ILLUMINATED FOR ABOUT 3 SECONDS. APPROX 5 MINUTES LATER IT CAME ON AGAIN, THIS TIME FOR 2-3 SECONDS AND WENT OUT. THIS CYCLED 3-4 TIMES IN THIS MANER. MAINTENANCE REMOVED AND REPLACED THE AFT BAG UPPER SMOKE DETECTOR. OPERATIONAL CHECK GOOD. AIRCRAFT RETURNED TO SERVICE.