What was found
WINDOW HEAT LIGHTS WON'T SHOW "ON" LIGHT DURING PREFLIGHT. GROUNDED - YES. PERFORMED WINDOW HEAT OPS CHECK. WINDOW OVERHEAT FUNCTION GOOD. WINDOW PWR FUNCTION GOOD. PERFORMED BITE OF WINDOW HEAT CONTROLLERS. BITE CHECK GOOD. NO FAULTS IAW B737-800 AMM 30-41-00. WINDOWS WERE IN DUN. SUSPECT THEY WERE PWR CYCLING AS NORMAL. OK FOR SERVICE. ONE BULB INOP ON INDICATOR. REMOVED AND REPLACED ONE BULB IN INDICATOR. LIGHTS CHECK GOOD.