What temp is the freezer at?
Here is a link to a Norcold Servcie maual
https://www.montanaowners.com/forums...?do=file&id=72 It may give you some ideas.
A 2005 is little long in the tooth for a refer. What happens when it is run on Propane?
Is there yellow powder in the back of the refer that indicates a leaking coil?
There are lots of stories here on replacing the cooling mechanism. Tat may be the best answer in your case.