What was found
MAIN CARGO DOOR RED LIGHT ILLUMINATED ON FLIGHT, ACCOMPANIED BY LATCH LOCK PINS NOT ENGAGED AMBER LIGHT ON MCD CONTROL PANEL.(FL 370, WITH 6.3 CABIN ALTITUDE AND 8.4PSI DIFF.) EXECUTED EMERGENCY CHECK LIST IAW AOM 5.2.6 AT 2 PSI DIFF ON DESCENT/DEPRESSURIZATION, BOTH LIGHTS WENT, CLEANED AND LUBRICATED LATCH PIN MECHANISM CLEANED AND LUBRICATED LATCH PIN SWITCHES AND CLEANED LATCH PIN SWITCH CONNECTOR PINS AND SOCKETS CARGO DOOR INSPECTION CHECK ACCOMPLISHED IAW MM 52-34-0 DOOR CYCLED SEVERAL TIMES COULD NOT FAULT AT THIS TIME.