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Is the fridge in an RV or not? IF it is in the RV, it may not be the fridge that is doing that. On LP mode there is no reason for it to do that as there is no AC use at all. I would test the heating element if you suspect a short there, but only after you plug it into an extension cord and make sure that something else isn't to blame. I am attaching a link to a Dometic Manual which should help here. If you need help with the testing let me know. http://bryantrv.com/docs2/docs/Mandiag.pdf
Then test the AC element with an ohmmeter and see if it is shorted out. OR it may be a short in the selector switch although that is pretty rare. Mice may have been at work chewing on the wiring. Check for that as well.
Just checking back in to see if you were able to sort this out or do you still need some additional input from me here?