As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
OIL PRESSURE LIGHT ILLUMINATES AT GROUND IDLE. NEW SWITCH NORMALLY WORKS WELL BUT ON OCCASION LOSES INTERNAL CALIBRATION OR IS MISCALIBRATED AS NEW SWITCHES SOMETIMES EXHIBIT THE SAME PROBLEM. SUGGEST A MORE MODERN DESIGN BE CONSIDERED FOR THIS PART. (K)