I think I've run into this once when I was doing a mover and their last setup was not SWM and the new system was. The HR23 wouldn't work, just a few random TPs with low signals but mostly 0s. Since I was putting in a SWM8, I unhooked the coax from a D11 and extended it to the HR23. I let it do its download on the one working tuner. Once it got picture, I went to Repeat Satellite Setup and connected back to the SWM line. It worked after that. I think it's a software glitch. Do you have another neighbor in the campground with a non-SWM setup that you can borrow off of for a temporary setup? If so, you have to keep the receiver powered up for the following entire process:
plug non-SWM line into your receiver and plug it in to power. Let it boot up to picture. You'll probably see a message saying one of the tuners is without signal. Once you have pic, navigate through the menu to Repeat Guided Setup. Once on the screen that gives you choices about your configuration, hook up the SWM line instead of the non-SWM line. Choose your correct setup (SWM3) and continue on the process. It should finish up. Bit of a pain in the butt but it should work. Once you get working, you might want to make sure you have the latest software in case they fixed the glitch in a future release.