Try this place.. I replaced one on my father in laws 5th wheeler several years ago, and replaced one on the driver side slide on my 39' 2003 Discovery.. They usually have videos on now to measure and replace and the cost was doable. as long as it is not under the patio awning, then there should not be any problem. Some of them the patio awning has to be removed to get the old one off.. here's the link....let me know if you can open it.
www.toughtopawnings.com