My AM/FM Radio in my 2006 Ford Crown Vic does not receive a signal. I have power, but no signal, I've been told the wire has likely come loose in the trunk area. Where would the wire for the antenna be located?

Your antenna is built into the rear window. You should be able to see the connection in the upper part of the trunk under the back window. If it isn't loose there, I suspect your antenna wire has come loose from the rear of your radio, or else the antenna wire is damaged somewhere in between the radio and the rear window. You'll have to pull it out and inspect it.

Assuming your car is automatic remove the pan inspect the transducer valve if transducer valve is okay put the Weeble shed back in the wall behold then your radio should work fine

Assuming they were referring to the power antenna (if your car is so equipt), it would be inside the trunck liner along the side where the antenna is. You will see the post of the antenna, the motor and the wiring from the motor.
Greg