pretty sure its between 2nd and 3rd plug, or this could be the case with the 1.8/2.0.

Does it have a/c? If so, put that on and the fans should cut in, at least you know they work. My focus 1.6 gauge never ever budged from half way either, and the fan would only cut in on the hottest of days being sat in traffic. Dont worry about it unless the gauge creeps past half way.