Rear air conditioning is a separate set of AC controls and vents for rear seat passengers. Many vehicles will use the same compressor for models with or without rear AC, but the lines are different, which means the drier filter and expansion valve will be unique, so this is something you need to pay more attention to if you’re buying a complete AC kit. It’s also worth mentioning that vehicles with rear AC have a second expansion valve for the rear, which is something to keep in mind when you’re diagnosing AC issues with your vehicle.
