What was found
CREW REPORTED RECEIVING CARGO DOOR CAUTION MESSAGE, FOLLOWED BY SERVICE DOOR CAUTION MESSAGE, FOLLOWED BY PASSENGER DOOR WARNING MESSAGE ON CLIMBOUT BELOW 1,000 FT AND GEAR RETRACTED. CREW RAN QRH, RETURNED TO FIELD AND LANDED SAFELY. MESSAGES NEVER EXTINGUISHED AND AFTER LANDING, RECEIVED AN OVERBOARD COOL FAIL STATUS MESSAGE. MAINTENANCE TROUBLESHOT, FOUND CARGO DOOR HARNESS SHORTED, R & R CARGO DOOR INDICATION HARNESS AND PERFORMED CHECKS IAW AMM. ACFT RELEASED FOR SERVICE.