I replaced the cooling unit myself in the Norcold fridge in our old hybrid. $1000, doing the work myself, was the cheapest I could get it, which was far cheaper than getting a dealer to do it, or replacing the entire fridge. There's lots of guides and videos on the Web that show how to do it, but it's still not for the faint of heart.
Ours was a victim of the infamous Norcold fridge recall a few years back. The dealer installed the factory-supplied kit, which was meant to prevent a fire in case of an ammonia leak, but did nothing to prevent the leak itself. Ours leaked, and we didn't realize the fridge wasn't working until we were loading it up for a trip, so I grabbed the electric cooler and we used that all weekend. When we got home, that's when I did a little more investigating, and sure enough, the cooling unit was leaking ammonia (yellow crusty stuff) from around the boiler: