What was found
LEFT SIDE WINDOW HEAT OVERHEAT LIGHT ILLUMINATED. LIGHT RETURNED AFTER COOL DOWN. GROUNDED - YES. P6-12 WINDOW HEAT POWER LEFT SIDE CIRCUIT BREAKER FOUND OUT. PERFORMED CIRCUIT BREAKER RESET REF B737-800 AMM 20-60-01. LEFT SIDE WINDOW HEAT CONTROL NOW OPS NORMAL. FAULT REVIEW SHOWS BUS POWER LOSS ON ALL FLIGHT LEGS EXPLAINED BY CIRCUIT BREAKER. LEFT SIDE WINDOW HEAT GROUND VERIFICATION TESTS GOOD REF AMM 30-41-00.