First, has it been diagnosed by a qualified technician or are you assuming it's you've "lost" it based on prior experience? It could be something simple like an internal fuse (there are at least two from the photo in this service manual:
https://lci-support-doc.s3.amazonaws..._rev_oc_lr.pdf
Is it possible that the control isn't broken but needs some attention? The above service manual has troubleshooting info.
It's also possible that something repairable has failed, a loose wire, bad solder joint, failed component, etc. It could even be a bad switch. One of the most common electronic parts to fail are electrolytic capacitors. These typically look like little metal cans and failed ones are either swollen or leaking. Do you have the old unit from the previous replacement? It could be a source for parts. No dealer or RV shop is going to attempt a repair, they're just going to pull and replace. You're going to need someone, professional or amateur who's experienced in electronic repairs.
How about one of the RV salvage yards?
I also notice that there is at least one eBay seller that sold one and sells similar parts. You might want to contact them.
https://www.ebay.com/p/1050130113
Linear Mode
