Not just the model, but is it a Dometic or a Norcold?. There should be a troubleshooting section in your refrigerators manual which should have been with your coach when you brought it. In addition to that, there are several troubleshooting guides on line.
Chris Bryant's RV site has several manuals available.
And don't believe a RV shop telling you that you need a new refrigerator!!! If you look closely in their eyes as their lips are moving, you will be able to see the $$$ signs! They make a big profit on those items. And before I put that kind of money into my rig, I'd consider installing a residential refrigator myself, but that is a entirely different topic. Find a mobile RV repairman. They are often much better than RV dealers when it comes to fixing stuff!!!