What was found
ACARS AND VERBAL FROM CAPTAIN`S R1 WINDOW HEAT, ON LEFT THIRD. INOPERATIVE DURING CRUISE AND ICED UP. RIGHT 2/3 WINDOW HEAT FEELS NORMAL. ACFT GROUNDED. ACCOMPLISHED WINDOW HEAT SYSTEM OPERATIONAL TEST IAW AMM 30-41-00-710-801, R1 WINDOW OPERATED NORMAL. ACCOMPLISHED WINDOW HEAT CONTROL UNIT SYSTEM TEST WITH NO FAULTS ON BITE IAW AMM 30-41-11-710-801. R1 WINDOW DUE TO ICE UP DURING CRUISE, REMOVED AND REPLACED THE R1 WINDOW IAW AMM 56-11-11/401, OPS AND LEAK CHECKED GOOD. CHECKED WINDOW TAP WIRING IAW WDM 30-41-12 AS H12.