What was found
THE CREW REPORTED A W/S 1 HEAT FAIL MESSAGE WITH A STRONG ODOR OF BURNING PLASTIC. THE ACFT LANDED WITHOUT INCIDENT, WHERE MAINTENANCE INSPECTED THE ACFT AND R & R THE NR 1 W/S TEMP CONTROLLER, OPERATIONALLY TESTED WITH NO DEFECTS, AND THE ACFT WAS APPROVED FOR RETURN TO SERVICE. DURING GROUND OPS FOR FLIGHT 5912, THE CREW AGAIN REPORTED A W/S 1 HEAT FAIL MESSAGE ASSOCIATED WITH A BURNING ODOR. MAINTENANCE INSPECTED THE ACFT AND FOUND CONTACTOR K0001 TO BE NOT DISENGAGING. THE CONTACTOR AND W/S 1 TEMP CONTROLLERS WERE R & R, OPERATIONALLY TESTED WITH NO DEFECTS NOTED, AND THE ACFT WAS APPROVED FOR RETURN TO SERVICE.