Smart air system not working

Smart air display has no power.
I fixed this when I first bought truck , think it was all dead batteries. Doubt that is the case now. Worked fine this morning.
F1 fuse is good and has power. All other fuses in box under bunk are good.
Battery management component was quite loose. I tightened up the nut on battery post. Ran engine to make sure full charge on batteries.
Have not checked any fuses in battery boxes.
Any idea why no power to this display?

Edit, I also put 12v to the red wire and then on yellow wire on display and it still did not light up

 

Well here is s good one. I went to Dave's APU. He said he won't work on one. Also peterbilt does not even know how go fix them. They call him all the time for advice and asking for parts that of course you can't buy.
So I guess it is back to my expert APU repair skills to figure it out.
Oh, and peterbilt in ks, the parts guy did not even know what a AGM battery was ( they are paccar branded) or that there were battery powered, apu's in Pete's.