As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE RIGHT FWD (R1) WINDOW OVERHEAT LIGHT ILLUMINATED ON THE GROUND IN SEATTLE. RAN QRH PROCEDURE, LIGHT EXTINGUISHED AND STAYED EXTINGUISHED. GROUNDED - YES. PERFORMED WINDOW HEAT CONTROL UNIT SYSTEM TEST AND FOUND NORMAL. NO FAULT FOUND REF B737-9 AMM 30-41-11-710-801.