What was found
WHEN WINDOW HEAT WAS TURNED ON DURING PREFLIGHT, SAW BRIGHT BURNING FIRE INSIDE CAPTAINS FWD WINDSHIELD. TURNED OFF SWITCH AND LIGHT/FIRE WENT OUT/ 2 MIN LATER, WINDSHIELD CRACKED 12 INCHES. REMOVED AND REPLACED LT FWD WINDOW IAW AMM 56-11. DURING THE REPLACEMENT OF THE WINDOW FOUND THE BLUE WIRE ON THE SPARE SENSOR TO HAVE A BROKEN RING TERMINAL. RETERMINATED WIRE PER SWPM CH 20. PERFORMED CABIN LEAK CHK IAW AMM 05-51. NO LEAKS NOTED. REMOVED AND REPLACED WHCU M321 IAW B737 AMM 30-41. OPS TEST GOOD. (9569562) AIRCRAFT WAS GROUNDED