What was found
ON TAKEOFF OUT OF ONT, THE LANDING GEAR DOOR WARNING LIGHT REMAINED ILLUMINATED. CYCLING THE LANDING GEAR EXTINGUISHED THE DOOR WARNING LIGHT. IN TOL, TROUBLESHOOTING REVEALED A HIGH RESISTANCE IN THE LEFT MLG DOOR UPLATCH SWITCH CIRCUIT CAUSED BY A CONTAMINATED ELECTRIAL CONNECTOR. THE ELECTRICAL CONNECTOR WAS CLEANED, RESTORING THE NORMAL OPERATION OF THE DOOR UPLATCH SWITCH. (M)