inside heater box behind glove box, if it is for auto climate control the wiring diagram they included is wrong. i just put one in and my fan went on high speed as soon as i turned on key, i changed a couple of wires around and it works correctly. dont ask me witch ones as i forgot, butt just look at the old one and the change of the new one and it will be obvious as that is what i did. i told ford they are selling parts that give missinformation and they dont give a dam. maybe so you will have to take it to them to fix butt screw that i would not let any of the ford jokers touch my car maybe my lawnmower butt not my SC.