Check boatandrvaccessories.com
Our 2007 Journey has its original GCH10A-4E. That is the model with the engine waste heat feature (Gas/Electric/engine radiator loop). Checked inside condition with an endoscope. Decided to replace. Looked everywhere. Found it there, although back ordered. Likely on one of those 70 container ships loitering off Long Beach.
They list Atwood parts.
Also RVPartsNation.com is a source.
Not difficult to replace electric element if not too corroded. Threaded fitting.
Wiring is simple bayonet connection. Take a photo of the element before removing. Then re- installing wires becomes "intuitively obvious to the most casual observer".
Fair Winds and Following Seas