Same problem - same solution . . .
I had the no-flow problem in our bathroom sink as well. We have a 2014 Flagstaff 27RLWS that's just come out of its 2nd winter here in the Charlotte area. When I began to check everything out for our first outing I discovered a zero flow condition (both hot and cold) in the bathroom sink. Everything else was fine. I determined that the shower and the john were supplied by the same plumbing. No valves or backflow devices separating them. I lamely tried to unscrew the faucet flow screen but was afraid I'd snap off the faucet it's so flimsy. Then I found this post and gave it a little more torque. Sure enough, clogged with small bits of tubing sawdust and other junk. Cleaned it out and it flows like a champ. I still like the idea of replacing the faucet thogh. But we're thinking about upgrading to a diesel pusher and going full time.
I also discovered that the outside shower fixture is in the OS in the O/S wall under the sink. And much to my horror there is absolutely no insulation between it and the inside of the trailer - two large gaping holes where the O/S shower hose pokes through. No wonder DW complains about drafts in the bath and bedroom! Got's figure out a way to correct that??
2014 Flagstaff 27RLWS
2007 Tundra XSP 5.7L