As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DESCENDING THROUGH 18,00' LEFT SIDE WINDOW OVERHEAT CAUTION ILLUMINATED. COMPLETED QRH PROCEDURE - WINDOW HEAT ILLUMINATED AGAIN. GROUNDED - YES. REF B737-900ER FIM 30-41 TASK 801 BITE SHOWS LH WINDOW SENSOR FAULT. VERIFIED FAULT REF FIM 30-41 TASK 811 PRIMARY SENSOR WAS OUT OF LIMITS. SWITCHED TO SPARE SENSOR. FAULT NO LONGER ACTIVE ALL TEST PASS WINDOW HEATS NORMALLY.