Here’s a dumb question:
Did you install the check valve backwards?
I installed it the way the first one was installed, which was on the tank and not the compressor. Double checked with support to verify it was the right way to do it.
Is there an arrow on the check valve indicating flow direction?
You could verify that it’s pointing towards the tank.
While trying to troubleshoot, I had also installed it compressor side to see if it would allow through, but still didn’t. I did check for an arrow but didn’t notice one.
Just got my new check valve and installed it. Air is going in the tank and it’s working. Now just to go around honking to make sure it is able to refill without blowing the fuse. 
Oh yeah, and I did notice the arrow behind the white sticker that said “in line check valve” and it was/is going the right direction.
Cool. I hope that solves your problem.
Had it refill about 5 or 6 times with no problems, so it all looks well now. Just my luck to have to get 2 bad check valves before a working one though lol. Now it’s time to get a more powerful compressor to really enjoy these things.
It was doing fine from the 19th to last night, but now fuses are blowing again. Is it really possible for the check valve to have gone bad that fast? I didn’t do anything out of the ordinary with the horns, just occasionally blew them. Already paid $30 for the first replacement leader hose/check valve with a valve that didn’t even work once, then paid $18 for this valve(although that is because I wanted it over night.) I’m really not looking to pay much more money when I already have what I assume is 3 bad check valves here.