As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(LOG 4565993) LH MAIN WINDSHIELD MAKING POPPING NOISES. FL280 LIGHT CLOUDS NO PRECIP . FOLLOWED QRH 1.13 FOR ARCING BUT SOUND STILL OCCURS. LATER IN FLIGHT OBSERVED STATIC SPARKS ON THE WIPER ARM. PERFORMED WINDOW HEAT CONTROL UNIT SYSTEM TEST(BITE) OPS CK NORMAL PER B737 AMM 30-41-11-710-801. ALSO PERFORMED WIPER SYS TEST, TEST GOOD PER B737 AMM 30-42.