As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING TAKEOFF FROM MSP, THE LEFT MAIN LANDING GEAR UNSAFE LIGHT REMAINED ON. RETURNED TO MSP AND LANDED WITHOUT INCIDENT. FOUND DIRT ON THE UPLIMIT SWITCH CANNON PLUG. CLEANED CANNON PLUG. REPLACED UPLIMIT SWITCH AND DOWNLOCK SWITCH PRECAUTIONARY. GEAR OPERATIONAL CHECKS WERE GOOD.