In order to get the right part at the right price you need to know where to look. There are many reliable dealers that will have contacts in the mechanics side of these vehicles who will be able to point you in the right direction. If you can identify the problem and which part needs replacing then you will make it easier for the mechanic to get hold of it.
If you are unsure or not 100% certain which part is failing then always seek advice from a professional, it will work out cheaper in the long run as you would hate to be buying and fitting the wrong part. If you have a friend who happens to be a mechanic then it will save you money as some faults may just be something simple.
There are many methods in which you could find the fault yourself, even if you have no knowledge of mechanics or how they work. You could ask around people who own RV’s as they may have had the exact same problem, many models are prone to having the same issues. You can also check on the internet on RV forums to speak to people all over the world which will increase your chance of finding the solution.
Check to see if the RV is still under warranty, if it is then the repair will be of no cost for you if it is something which is unavoidable. If you’re buying a second hand RV get a mechanic to check over it to make sure it’s mechanically sound and not liable to any faults.