240 Power antenna not working; what is this disconnected wire?

My power antenna, which used to go up and down (noisily), stopped working, either before or after I installed a new radio. I believe I've got the radio hooked up correctly, but I removed the spare tire the other day and found this. It comes from the mast connector there and goes to nothing.



Where is this supposed to go?

Ground wire.....find a place to ground to the body.You can see the eyelet is broken. That screw holding the antenna motor to the body looks like a good place.....