Air conditioner with flow homogenizer

The heating and air conditioning system for a vehicle has a heat exchanger (4) which is connected to a coolant circuit (5) and mounted in the main air channel (3). Deflector plates (13a, 13b) whose ends are curved towards the center of the channel are mounted downstream from the exchanger to homogenize the air flow before it enters the ducts (10a, 10b) directed to the driver and passenger.