Why won't my car turn off after key is removed

What is your question?

I went to start my car and it would not start. I had power so I replaced the starter and wasn't the problem. There's some kind of buzzing sound in the engine that is causing my car to not start and drains the battery if I don't unhook it. Do you know what it could be? The sound seems to be coming from the wire harness and will start as long as there's no buzzing sound.

How long has your 2002 Ford Escape had this problem?

a few months