As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
MSP - FLT 3218 - ON CLIMB-OUT FROM MSP, THE GEAR WARNING HORN SOUNDED. THE WARNING HORN CONTINUED TO SOUND UNTIL THE GEAR WAS SELECTED DOWN. THE AIRCRAFT RETURNED TO MSP. MAINTENANCE REPLACED A MICROSWITCH AT THE RIGHT POWER LEVER. SYSTEM OPERATED SATISFACTORILY. (X)