As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING FLIGHT, A SLIGHT 'SQUEAL' NOISE WAS HEARD FOLLOWED BY A BURNED RUBBER ODOR. THE AIR CONDITIONER WAS SWITCHED OFF, THE NOISE QUIT. ACFT MADE A PRECAUTIONARY LANDING AT A LOCAL AIRPORT. THE AIR CONDITIONER COMPRESSOR HAD LOCKED UP AND BURNED THE DRIVE BELT.