As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LEFT FWD WINDOW OVERHEAT LIGHT ILLUMINATED- STAYED ON AFTER QRH PROCEDURE. GROUNDED - YES. PERFORMED BIT CHECK PER B737-800 FIM 30-41 TASK 812 WITH SENSOR ILLUMINATED. SWAPPED TO SPARE SENSOR- NO HELP, SWAPPED WHCU CONTROL BOX NO HELP REINSTALLED ORIGINAL WHCU CONTROL BOX. REMOVED AND REPLACED LH FWD (L1) WINDOW REF B737-800 AMM 56-11-11 GROUND VERIFICATION SUCCESSFUL. WINDOW OVERHEAT LIGHT REMAINS EXTINGUISHED DURING TEST.