Yahoo Message Number: 95341 (http://groups.yahoo.com/neo/groups/Country-Coach-Owners/conversations/messages/95341)
The engine ecm has a wire that comes directly off the battery, not thru the key, it is for memory of the ecm.
If this wire or its fuse has corrosion, blown fuse, or another fault it will cause what you are saying.
May not be it but worth a check.
Mikee