As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LEVEL AT INITIAL CRUISE "L SIDE" OVERHEAT ILLUMINATED. RAN QRH. LIGHT STAYED ON. TURNED SWITCHED OFF PER QRH. GROUNDED - YES. WINDOW H16 VERIFIED TO BE ON #1 TAP PER B737-900 WIRING DIAGRAM MANUAL 30-41-12. CHECKED RESISTANCE AND VERIFIED IT AT 59 OHMS. REMOVED AND REPLACED L2 WINDOW REF B737-900 AMM 56-12-11-400-801. WINDOW HEAT OPS CHECK GOOD REF B737-900 AMM 30-41-00. L SIDE OVERHEAT LIGHT REMAINED EXTINGUISHED, LEAK CHECK GOOD.