It's pretty easy to do. I can't post a scematic but will try to email you a drawing of it. The relay is operated by aa green/wht wire, which provides a path to ground for the coil inside the relay. Normally, the cooling fan switch on the engine grounds this wire, as does the air conditioner. All you need to do, is find this green/wht wire where it comes into the car from the front compartment. It depend where you want to put your manual switch. The wire comes in, near the steering column, in bundle of wires. It can also be found in the center console, as it makes it's way back to the engine compartment. Just splice into the green/wht wire, without cutting it. Connect the other end of the splice wire to one side of your switch. Run a ground wire to the other siide of the switch, and you are in business. This will allow the normal functions of the cooling fan circuit to work just as they always have, but also allows you to turn it on at will.