I'm not a trained electrican so I'll try to be specific.I have an existing timed exhaust fan with a three way switch(one light,two switches)and I want to put a new one in to replace the old one.the new one has a green wire black wire and two white I want to make sure the fan doesn't come on every time the light comes on. I did not open up the old fixture yet as I won't start the project 'till next week. I don't want to run into any issues. Just want to make sure I do it correctly. Thanks in advance... mike

Doesn't it have installation instructions? Google the brand and model for details. We have no idea of the make, model, wiring diagram, how it was wired and mind readers are in short supply today or they would have answered the question. Why not look to see how the old one was wired.