As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
STRONG HEAT SMELL WHEN WINDSHIELD HEAT SELECTED ON. MAINTENANCE FOUND EFIS COOLING TUBE CHAFING ON CONTACT (A2) OF PILOTS WINDOW HEAT RELAY (LOW) K118. REPOSTIONED TUBE AND PROTECTIVE BOOTS ON RELAY CONTACTS. ALSO FOUND HIGH HEAT RELAY K119 MAKING HUMMING SOUND. REPLACED K119 WITH NEW RELAY P/N MS24166-D1. OP CHECKS OK.