As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CANNON PLUG FOR PRESSURE SWITCH HAD LOSE CONNECTIONS IN PLUG WHICH CAUSED RED XMSN OIL PRESS LIGHT. HAD TO REMOVED CANNON PLUG AND REINSTALL PINS. PULLED AND CLEANED CANNON PLUG FOR PRESSURE TRANSDUCER COULD NOT DUPLICATE DROP IN PRESSURE. PREFORMED OP GROUND RUN NO DEFECTS NOTED. AC THEN RETURNED TO BASE NO ISSUES. AFTER PILOTS SWAPPED OUT ON THE WAY TO GET FUEL HAD A FLICKER OF THE XMSN OIL PRESSURE LIGHT. THE PRESSURE SWITCH WAS THEN REMOVED AND REPLACED WITH SERVICEABLE ONE. PREFORMED OP CHECK FLIGHT CHECK GOOD. NO OTHER DEFECTS NOTED.