Mine is also a manual valve. I would suspect the location depends a lot on the model of your RV. My frig is in the slide and, the water shutoff is located inside the lower outside access panel.
Brian, Loretta & Daisy (Golden Retriever)
2008 Holiday Rambler Endeavor PDQ40 2014 Ford Explorer toad
In the same bay as your 12V water pump you should have a water manifold with red/hot and blue/cold valves. The ice maker will be paired with something else...maybe the cold for a sink and it should be labeled. There should be a tool on the manifold to turn the valves on/off. There may be another valve under the sink to turn just the ice maker off.
This post is my opinion (free advice). It is not intended to influence anyone's judgment nor do I advocate anyone do what I propose. Sold 04 Dynasty to our son after 14 great years. Upgraded with a 08 HR Navigator 45โ...
Depends what you're trying so accomplish. Turning off the ice maker is just lifting the feeler wire. On ours, and I suspect most others there is no valve except for the water filter feeding it and the sink drink dispenser