Electronic unit comprises an housing comprising a top cover; a printed circuit board mounted inside the housing and comprising at least a first heating source element on the top layer of the printed circuit board; the top cover comprises at least a first opening; the electronic unit comprises at least a first thermally conductive insert element distinct from the housing and extending from its top extremity arranged around the first opening, to its bottom extremity in thermal contact with the first heating source element such that heating dissipation of the first heating source element is allowed; fixing means configured to entirely fix the top extremity of the first thermally conductive insert element with the top cover around the first opening.