What was found
DURING PRE-FLIGHT HAD "OVERHEAT" LT ILLUM FOR R2 WINDOW. ACCOMPLISHED QRH PROC & TURNED IT OFF FOR MORE THAN 6 MINUTES. WINDOW WAS STILL HOT TO TOUCH AND "OVERHEAT" LT ILLUM. AGAIN IMMEDIATELY AFTER TURNING THE SWITCH TO "ON" AGAIN. GROUNDED - YES. INTERROGATED WHCU BOX AND FOUND "WINDOW SENSOR" FAULT REF FIM 30-41 TASK 801. ALSO FOUND R2 WINDOW DELAMINATION IN CENTER OF WINDOW APPROX 8"X8" AND NOT WITHIN LIMITS PER AMM 56-12-11. REMOVED AND REPLACED R2 WINDOW REF AMM 56-12-11. PERFORMED LEAK CHECK PER AMM 05-51-91. NO LEAKS NOTED. PERFORMED WINDOW HEAT SYSTEM OPS CHECK PER AMM 30-41-00. OPS CHECK GOOD. NO OVERHEAT LIGHT NOTED.