As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
INVESTIGATION OF THE PROBLEM WITH THE RIGHT FUEL GAUGE SHOWING FULL ALL THE TIME, REVEALED THE GAUGE ITSELF IS INOP. REPLACEMENT OF THE GAUGE ONLY, CORRECTED THE PROBLEM. THE ONLY COMMENT IS THAT THE AGE OF THE GAUGE MORE THAN THE TOTAL TIME CAUSED THE PROBLEM. THE GAUGE IS ORIGINAL EQUIPMENT AND THE AIRCRAFT IS A 1966 MODEL.