As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON CLIMBOUT DURING FLIGHT 2701, AVIONICS SMOKE LIGHT ILLUMINATED. WITH NO SMOKE OR FIRE PRESENT IN COCKPIT OR CABIN. AIR RETURN TO DTW. MAINTENANCE INSTALLED SERVICABLE AVIONICS RACK SMOKE DETECTOR PN 72-111211-000 SN/OFF A2501, SN/ON A5149. ALL CHECK FOOD DONE IAW AMM.