As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
L SIDE WINDOW (L2 WINDOW) OVERHEAT LIGHT ILLUMINATED IN CRUISE. PER QRH HEAT SELECTED OFF FOR 5 MINUTES, THEN BACK ON. NORMAL OPERATION THEREAFTER. GROUNDED - YES. ACCOMPLISHED B737-9 IFIM TASK 30-41-00-41-00-810-835. INITIAL EVALUATION PASSES.