Abstract: The air intake neck comprises a body 1 in two semi-shells 1a, 1b which define a mixing chamber 2 onto which open a cold air conduit 3 and a hot air conduit 7 which communicate with an outlet conduit 12 for the mixed air mixed in the mixing chamber 2. The hot air conduit 7 is separated from the mixing chamber 2 by a thermostatically adjusted flap 9 which is controlled, through a linkage 21, 26, 27, by a thermometric sensor 17. The latter is connected to the body 1 and provided in a position in which the mixed air flows thereover. The linkage comprises transmission elements 21, 26, 27 which are exclusively mounted in translation in the body 1 and include at least one motion direction changing device 27.