THE FUEL HEATER WIRING ON 7.3L DIESEL ENGINES HAS HAD AN ELECTRICAL FIRE ON 3 OF OUR VEHICLES OUT OF THE 28 IN OPERATION WITH THIS ENGINE. THE CONNECTOR IS A PUSH ON SPADE WITH A RUBBER SURROUND TO HOLD IT IN PLACE. ONE FIRE THAT WAS SEEN IN PERSON WAS SMALL (FEW INCHES) THE OTHERS WERE FOUND AFTER THE FIRE HAD OCCURRED. THE FIRE THAT WAS VIEWED OCCURRED WHEN THE VEHICLE WAS PARKED, FIRST START OF THE DAY AND LESS THAN 10 MINUTES IDLE TIME. I BELIEVE THE RUBBER SURROUND DOES NOT PROPERLY SUPPORT THE TERMINAL AND CREATES A LOOSE CONNECTION THAT ARCS AND OVERHEATS THE RUBBER, THEN IGNITING THE SMALL FIRE.