A timely post...
I need the same information. In my case, the refer is a Norcold unit. Apparently, I will have to disconnect a gas line, the electricals, and remove some screws to pull the unit out of the wall in order to gain access to the rear. Has anyone out there done this? I downloaded the manual for this unit from the Norcold website.
On my previous RV, I replaced the element on a Dometic unit. On that model, the element slipped into a well. It is critical that the replacement element is the correct one for the unit as its length, dimensions, and placement ensure that heat will be delivered to a critical spot.
If your Dometic is made the same, find the well and you are home free.