On my 2006 Journey it is located under the dash gauge cover that surrounds the guages, on the back - left side. It is a small black box, maybe four or five inches square with a decal on the top, mounted on the dash plate. It was simple to remove the dash gauge cover, just unscrew the five or six screws and lift off, there may be a speaker wire attached on the left side by the driver's window. Just be careful to cover up the defroster vents with a towel so that if a screw gets away when removing them, it does not go down into those vents.
It was interesting to look at all the stuff under there and while I had the cover off, I straightened up one of the air pressure gauges that was slightly off center.
Here is the link to the wiring diagram for a 2005 Journey 36G which shows the location of the module on page 5 of the .pdf:
http://www.winnebagoind.com/diagram/...ire_148556.pdf
You can also look up your model on the Winnebago website if not a 2005 Journey 36G under "resources" and then "manuals & diagrams" and then "wiring diagrams", then pick your year and model, etc..