First thing to do is to start the engine and test again, in case there is a 12V charge circuit that needs the ignition to be on in order to send 12V to the pin on the hitch connector.
If it fails that test, you may have some work to do. Ford does not provide a 12V charge circuit when it ships the F-53 chassis to Fleetwood. If there is a charge circuit, Fleetwood would have installed it. If Fleetwood did not install a charge circuit, you will need to install one yourself.
2008 Holiday Rambler Admiral 30PDD (Ford F-53 chassis)
2009 Honda Fit Sport