Dometic fridge

Sorry for the hasty post as I have been trying to figure this out in between work and just wanted to see if any of you guys had some ideas? We recently acquired a 1988 kit companion camper. My dad bought it a few years ago, lived in it for month and it’s sat ever since. He wanted it to get used so he gave it to us. So far all it’s needed is a very deep cleaning and reseal. The only thing I can’t get to work is the fridge.

It is a dometic rm 2601 my dad used it when he got the trailer and said it worked great well now the fridge won’t get cold. The freezer gets a little cold but and the fridge might just barely sometimes be a little colder than outside. It does the same thing on gas or electric and Iv checked the temps of the coils in the back and they seem pretty even the hottest being 150 degrees up higher.

Is there any other diagnostic thins I can do to figure this out? I noticed there is a single wire that goes to the fins in the fridge that I’m assuming to be a temperature sensor for the thermostat. And since the freezer gets coldish I I wondered if maybe the thermostat wasn’t working?

We are trying to go camping this weekend so hopefully is ya a easy fix if not we will be using it as a ice chest.

Thanks for your input!!!