Morning! At least where I am!
Water is always a good thing to look over the drawings to see where the lines run and what might stop flow.
So it may seem picky but knowing which of the two 32 foot Brave you have may come into play if we need to get a deeper look!
The plumbing drawings start here but we may need to look at the specific one you have.
https://www.winnebago.com/Files/File...m/Plumbing.htm
Can you sort it out from these two? The water inlet is where I started looking and there is a difference right at that point, so better to chase the right info!
If this is not on top of the head, there should be a label near the drivers seat with those details.
But I might have a thought on the vanity as it appears to be about the first stop from the city pressure inlet. Looks like it comes in and then goes up pretty directly.
With that small amount of stuff involved. I might guess first that the strainer on the vanity may be stopped up with minerals. Maybe hard water or just debris which then set up solidly while stored? Do you have a strainer that can be unscrewed to clear it?
Maybe soak in vinegar to soften them?
Example of what I see on sheet 4 of one model and the other is close to same on this portion. Not much in the line to keep cold water from going in to vanity as a starter?
Click this snip or go direct for better view!
If that idea falls flat ( I do that!) can you tell us a bit more about how you are working the problem and what you get? I might go with getting cold water to flow first as it travels a more direct route than water which has to go to the water heater and then back to where we use it.
I do the simple thinking before testing my brain too far!
See if that does anything and let us know what else we might chase down as you work through the details?