As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ORD - FLT 1525 - LEFT MAIN LANDING GEAR INDICATOR STAYED RED AFTER GEAR RETRACTION FOLLOWED QRH AND HAD NORMAL INDICATIONS AFTER. REMOVED AND REPLACED LEFT MLG UPLOCK PROX SENSOR. PERFORMED OPS CHECK OF SENSOR THROUGH PROX SWITCH ELECT. (M)