As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DTW - FLT 640 - RIGHT ICE PROTECT TEMP LOW LIGHT DID NOT ILLUMINATE WHEN AIRFOIL ANTI-ICE SELECTED ON. LIGHT DID TEST, BUT DID NOT ILLUMINATE WITH THE RIGHT ICE PROTECT TEMP LOW LIGHT, WAS ABLE TO DUPLICATE DISCREPANCY. CLEANED ELEC CONNECTOR AT RIGHT AIRFOIL. ANTI-ICE LOW TEMP SENSOR SYSTEM OPS CHECK GOOD IAW 30-10-0. (M)