As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LEFT SIDE WINDOW OVERHEAT LIGHT ILLUMINATED ON DESCENT INTO SEATTLE. GROUNDED - YES. WHCU BIT VERIFY TEST PASS, SENSOR FAULT FOR PREVIOUS LEG. OBSERVED SPARE SENSOR IN USE. RESISTANCE CKS WITHIN LIMITS & SAME VALUE FOR BOTH SENSOR, HEAT FILM CHECKED NORMAL. SHOOK DOWN COIL CORD DURING OPS CKS, UNABLE TO DUPLICATE FAULT REF B737-900 AMM 30-41-21 & 30-41-00.