What was found
WINDSHIELD HEAT FAIL L CAS ILLUMINATED. DURING DESCENT FROM FL400 THE WSHLD HEAT INOP L CAS MESSAGE ILLUMINATED WITH AN ASSOCIATED SMELL OF BURNT ELECTRICS. WE TURNED OFF THE LEFT WINDSHIELD HEAT AND AS WE CONTINUED THE DESCENT THE WINDSHIELD FELT WARMER THAN NORMAL TO THE TOUCH AND THE BURNING SMELL PERSISTED THOUGH NOT AS STRONG AS BEFORE. PULLED THE L WINDSHIELD CIRCUIT BREAKER AND THE SMELL WENT AWAY AND THE WINDSHIELD COOLED DOWN. WE WERE IN CLOUD BUT NOT ICING CONDITIONS DURING THE EVENT. REMOVED & REPLACED DEFECTIVE LT WINDSHIELD CONTROLLER IAW MM 30-41-00.