As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AT LEVEL OFF AT FL300. LEFT SIDE WINDOW HEAT OVERHEAT LIGHT ILLUMINATED. SELECTED OFF PER QRH PROCEDURE. RESELECTED ON AFTER THREE MINUTES AND LIGHT REMAINED EXTINGUISHED. GROUNDED - YES. SELECTED OFF PER QRH PROCEDURE. RESELECTED ON AFTER THREE MINUTES AND LIGHT REMAINED EXTINGUISHED.