As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
L2 WINDOW HEAT OVERHEAT LIGHT ILLUMINATED IN FLIGHT. RAN QRH PROCEDURE AND LIGHT EXTINGUISHED. GROUNDED - YES. PERFORMED WHCU BITE PROCEDURE REF B737-900 FIM 30-41 TASK 801, NO CURRENT FAULT LOGGED, FOUND HISTORY FAULT FOR WINDOW SENSOR. WINDOW HEAT SYSTEM WORKING NORMAL AT THIS TIME.