Welcome to the forum John.
Is the fridge a combo LP gas and electric?
The old fridge had a 5 amp fuse for electric element and 12 amp fuse for 12v on control board on back of fridge, your talking about the main 12v fuse in fuse panel I believe.
The control board maybe feeding back a problem to main fuse board.
In the links below in my signature RV Appliances there are spec's for the fridge for chasing problems.
This link has many more items you may need sometime also.
If dealer is a distance from you give Newmar a call for Mobil Tech which they have trained.
Sorry for your problem, I had a few myself with my new coach, should not happen.