As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON DEPARTURE FROM DTW, THE LT ENGINE ANTI ICE WARNING LIGHT ILLUMINATED. THE FLIGHT RETURNED FOR CORRECTIVE ACTION AND LANDED WITHOUT FURTHER INCIDENT. OHMED THERMISTORS AND FOUND THERMISTOR 3 WOULD INTERMITTENTLY OPEN UP WHILE COOLING. UNUSED THERMISTOR 5 BAD AS WELL. SWITCHED THERMISTOR 3 TO SPARE 4. RAN 30 MINUTES. ALL CHECKS GOOD.