What was found
RECEIVED "MAIN CARGO DOOR" EICAS ALERT AT CRUISE. OCCURED AT FL 370. REMOVED AND MOUNTED S892 REF B767 AMM 52-71-09-2, REQUIRES AVIONICS TO TERMINATE CONNECTION AND CHECK OUT SPLICED IN SENSOR S892 IAW B767 MM 52-71-09-2 AND SSM 52-70-01. ADDITIONAL MAINTENANCE ACTION REQUIRED. OPS CHECK GOOD. REF AMM 52-71-09-2 AND 52-71-00-5.RAN QRH AND DESCENDED TO 15,000'. PASSING APPROX 16,000' LIGHT WENT OUT. NO CHANGES IN PRESSURIZATION.