To be clear.... Your OEM ford 3 button remote will not unlock any of your 3 doors ? (2 cab doors and the main house entry door).
First Check that all fuses are good
Does the lock/unlock button on the door armrest work ? if yes proceed if NO then it's not the RKE module. Winnebago only uses the ford RKE module to lock / unlock the house door.
The Ford RKE (Remote Key Entry) Module for the factory remotes is located behind the right (passenger) side pick panel in the Cab (you will need to remove the plastic entry step liner & then the right kick panel no tools required as they are held in place by Snaps / push pin etc).
The module is towards the upper side & forward and is labeled. Don't remove the module yet.... try to unplug the 2 modular plugs & wait 10 - 15 seconds before re-plugging back in. This cycling seems to fix most issues.
If ONLY the house door won't unlock with remote, check the 2 brass spring loaded contacts on both the door side & the frame side to make sure they are clean & making proper contact.
Last if still no go you can try to reprogram the remote by opening the drivers door hitting the unlock button on the door arm & then cycle the Key in the ignition switch from off to on QUICKLY 8 times leaving in the ON position on the 8th turn, within 10 seconds push any of the buttons on the remote if successful the door locks will cycle, then turn the key off.