As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING FLIGHT 2999/2798, RT INTAKE HEAT LIGHT ILLUMINATED AFTER TAKEOFF. AIR RETURN TO DTW. MAINTENANCE PERFORMED VISUAL INSPECTION OF ALL DUCTING. NO DEFECTS NOTED. PERFORMED 1 HOUR GROUND RUN OF SYSTEM WITH NO FAULTS NOTED. COULD NOT DUPLICATE DISCREPANCY. ALL CHECKS GOOD. REF SAAB AMM CH 30/71.