[Vern M.] Open the outside door. Plug in? Circuit breaker okay? Fuse in line anywhere out there (I don't any longer own a Dometic so can't remember). Feel heat in the right place when power control says it is on? If all of the above are working, it's time to call/see a Dometic service outlet.
[Gary R.] I have a new Dometic RM1272 and it would work perfect on Gas but would start to warm up when switched to electric. It was still under warranty so I took it in and the repairman said that there were TWO heaters for electricity and only one was working! He said he changed the bad one out and now it works good. I never knew that there were two heaters for electric! Good luck Gary.
There is a great web site that gives schematics and trouble shooting guide for rv refrig's. I will look for the info in the morning and give you the info. It's 11:30 pm now. Its a great site.