As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
#1 OIL PRESSURE LIGHT ILLUMINATED. PRESSURE/TEMP. GOOD. #1 THROTTLE TO IDLE. LIGHT REMAINED ON. SECURED ENGINE. RAN ENGINE, NO DISCREPANCY, DISCONNECTED BOTH OIL MAIN WARNING SWITCHES. MEGGED WIRE FROM DIM BOX, NO DISCREPANCY. ON INSPECTION, FOUND DIFFERENTIAL OIL PRESSURE SWITCH DAMAGED EXTERNALLY. HOLE IN CASE. REPLACED SWITCH IAW DC-8 MM 79-33-01-2. OPS AND LEAK CHECKED GOOD ON ENGINE RUN.