[clepp]

Most of the furnace should be accessible from the outside if you remove the cover where the vents are located. There's one located in either side. Livingroom furnace is located on the drivers side and the galley furnace is located on the passenger side. I attached a couple of pictures showing the locations on my coach. They could be different on the 2004, but the vents should look the same. You will need sealing putty to put the covers back on after you remove them. The igniter is hard to get at though. From what I remember it is buried somewhere near the middle and may require pulling the entire unit out or removing a large portion to repair it. Lots of youtube videos about the Dometic Atwood furnaces that may be helpful.