First, welcome to the forum.
About your question, I've not installed that paticular radio, but the radios used in Airstreams are basically aftermarket automotive units. Typically they have two power input wires, one of them is a higher current wire that is switched on and off with the ignition in the car, and the other is normally constant on and is used to keep the memory "alive" in the radio when the ignition is off.
When these radios are installed in Airstreams it is common to wire both circuits into one, so they are both hot all the time. If you have done this, and the radio does not work, check that you did not blow the fuse in the Airstream. Then check to see you do have a good ground.
"To compel a man to subsidize with his taxes the propagation of ideas which he disbelieves and abhors is sinful and tyrannical."-- Thomas Jefferson