2003 Impreza Outback Sport Knock Sensor Wiring

[scottrussell01]

So, I got a check engine light. Code reader states knock sensor. I order a knock sensor. Go to remove the old one and there is no wire connected. I can not find a stray wire anywhere. I have a problem with squirrels getting into my engine compartment at work and chewing on things. My guess is that is the issue. where does the wire from the knock sensor go to? I am assuming I need to replace it all the way back to the next connection but, where is that. And, can I even purchase the wiring setup?