What was found
THE FLIGHT CREW REPORTED THAT DURING CLOSING THE CABIN DOOR FOR FLIGHT THE CABIN DOOR ANNUNCIATOR REMAINED ILLUMINATED. THE SCHEDULED FLIGHT WAS CANCELLED. THE MAINTENANCE VENDOR REPLACED THE DEFECTIVE MAIN DOOR VENT SOLENOID WITH AN NEW SOLENOID RIGGED AND RETURNED TO SERVICE. UPON PREFLIGHT FOR RETURN TO SERVICE IT WAS FOUND THAT THE NEW VENT SOLENOID HAD FAILED AND REQUIRED TO BE REPLACED. A SECOND NEW DOOR VENT SOLENOID WAS INSTALLED AND RIGGED BY THE MAINTENANCE VENDOR. FUNCTIONAL CHECKS WERE SATISFACTORY AND THE AIRCRAFT WAS RETURNED TO SERVICE. THIS REPORT OF A FAILED DOOR VENT SOLENOID FOLLOWS MANY OTHER SDR REPORTING OF THIS COMPONENT.