If your Club Wagon *does* have rear AC, the controls are typically located on the rear of the center console, near the rear passenger area. It might be a simple set of vents with only on/off control, or possibly a more sophisticated system with temperature adjustment. Look closely at the console area between the front and rear seats. There might be a small panel or a series of vents that aren't obviously related to the front AC.
If you can't find any controls, it's highly likely your vehicle wasn't equipped with rear AC from the factory.
