As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DTW - FLT 2816 - LEFT INTAKE LIGHT CYCLES ON/OFF EVERY 10/20 SECONDS, OVERHEAD AND CWP LIGHTS ILLUMINATED NORMALLY. MASTER CAUTION CHIME AND CAUTION LIGHT DID NOT WORK. RETURNED TO DTW. MAINTENANCE REPLACED LEFT DE-ICE CONTROL MODULE IAW SAAB AMM CH 30. PERFORMED 10 MINUTE GROUND RUN, NO FAULTS NOTED. (M)