As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LEFT SIDE WINDOW OVERHEAT LIGHT ILLUMINATED 20 MINUTES INTO FLIGHT CYCLED SWITCH OFF FOR 5 MINUTES. OVERHEAT LIGHT REILLUMINATED AFTER TURNING SWITCH BACK ON. GROUNDED - YES. DUE TO HISTORY AND NO FAULT FOUND, REPLACED WINDOW HEAT UNIT PER B737-900 AMM 30-41-11/401. TEST GOOD PER AMM 30-41-501.