So I got my radio harness adapter and faceplate yesterday. I'm installing today and came across a 3rd harness connected to the top of stock stereo. So my question is what is this harness for? Where does it go for my aftermarket radio? Do I have to have it connected? First pic is my harness adapters connected and the 3rd one at top in question. Bottom pic is back of stock stereo where 3rd connector plugged in.