My Dometic RM2354 has a choice of Propane, AC, DC, and Auto. Auto prefers AC. It has an AC led too. DC is just a maintain cold, kinda weak.
Does propane work? If it does maybe you have a blown AC fuse.
Here is a manual:
http://rvrefrigeratorrepair.com/wp-c...ice-RM7030.pdf
Controls are in section 1 page 5
Some basics: Are you level? Unlevel operation can be a fire hazard. Also doesn't cold. Be within 3 degrees side to side (facing frige door) and 6 degrees front to back.