As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
L FWD WINDOW HEAT CAUTION AT CRUISE. GROUNDED - YES. FOUND WHCU SHOWING SENSOR FAULT IN BITE. PERFORMED TEMPERATURE SENSOR RESISTANCE MEASUREMENT PER AMM TASK 30-41-21-760-801. FOUND PRIMARY SENSOR ON L1 WINDOW OPEN. SWITCHED WINDOW TO SPARE SENSOR AND SENSOR READS WITHIN LIMITS AND WINDOW NOW OPERATES NORMALLY.