As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON CLIMB THRU FL280 R2 WINDOW OVERHEAT ILLUMINATED. RAN CHECKLIST LIGHT EXTINGUISHED AND REMAINED OFF REMAINDER OF THE FLIGHT. GROUNDED-YES. CHECK HISTORY AND BITE CHECK ON WINDOW HEAT CONTROLLER UNIT, IAW B737-900 FIM 30-41 TASK 801, NO FAULTS NOTED. OK FOR SERVICE.