Preassembled rear module of a cabin of a heavy vehicle.

Vehicle such as a land tractor having a cabin (1) with a heating, ventilating and air conditioning system, said cabin (1) comprising an air duct assembly (12) with at least a first air duct (14) configured to be coupled to the intake of an air processing unit (2) of the heating, ventilating and air conditioning system, and supporting means for attaching electronic devices (40), the air duct assembly (12) and the supporting means being preassembled together so as to form one single module (13).