What was found
(CAN) ON A FLIGHT, BEFORE ENTERING THE ETOPS ZONE, THE WINDOW OVERHEAT CAUTION LIGHT ILLUMINATED FOR THE LT SIDE SLIDING WINDOW, L2. THE CREW CONSULTED THE NON NORMAL CHECKLIST AND PERFORMED A RESET. THE OVERHEAT LIGHT ILLUMINATED A SECOND TIME AND THE CREW SELECTED THE LT SIDE WINDOW HEAT SWITCH TO OFF AND PERFORMED AN AIR TURN BACK. MAINTENANCE DETERMINED THE SLIDING WINDOW ELECTRICAL CORD, CURLY CORD, WAS AT FAULT AND WAS REPLACED.