An electrical connector assembly of a fuel injector includes a body with external walls defining an internal volume and an internal wall dividing the connector in a first part adapted to be fixed in a complementary engagement with the body of the injector and, in a second part adapted to receive another electrical connector. The electrical connector assembly also includes at least one electrical terminal extending through the internal wall from an inner extremity protruding in the inner volume of the first part of the body, to an outer extremity protruding in the outer volume of the second part of the body. The outer extremity is shaped to receive in a complementary engagement an electrical terminal of said another electrical connector. The connector assembly is adapted to be in fluid communication with the back leak return conduit of the injector.