As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CLIMB, THE LEFT MAIN GEAR UNSAFE LIGHT REMAINED ON WITH THE GEAR HANDLE UP. RECYCLED GEAR AND VERIFIED LEFT MAIN GEAR DOOR WAS UP AND LOCKED. FLIGHT CONTINUED TO DTW AND LANDED WITHOUT INCIDENT. MAINTENANCE REPLACED THE DOWNLOCK PROXIMITY SWITCH.