Can I fix my fridge in my Motorhome?

My fridge was working on one camp site and when we moved we found that for some reason it now won't work on either. I have checked the fuses and they are set at working, even the fuse box in the cupboard is saying that everything is ok. At first the gas would light but not cool the fridge. Now that wont work either. I don't think that the fridge works on the car battery when we run either. Is the fridge finally dead after ten years or is there something that we don't know about it. I have had a suggestion that it might need more gas. Is this possible, or do we finally have to buy a new fridge.