I have put aside the issue of the yellow wire for the time being as you suggested. for right now both the yellow wire from the LSS2 and HDS8 are connected and butt connected to a hot wire to the battery with an in-line fuse. .
You told me earlier that this is what your buddy told you to DO, not what you DID. I told you to leave it alone. I did not bother to try to explain that he was very wrong as the effort would have likely been futile. You didn't tell me you actually DID connect it to the battery until now or I would have warned you then.
You will soon have a dead battery, hence my courtesy reply to tell you about that bad move. What you have done causes the LSS box to be powered up 24/7. The yellow wires should be connected together - period. This means no fuse, no wire to the battery, nothing - JUST connect the yellow wires together.
Since you indicated you can read and follow directions, why would you do as your buddy suggested with the yellow wires considering that the Lowrance installation instructions are VERY clear on what to do with the yellow wires? Lowrance even has illustrations showing what to connect and how. If the yellow wires should be connected directly to the battery, that would have been shown in the illustrations!
You NEVER DID do the waypoint test I told you to try and I think I told you twice to do it. You never explained why you weren't following instructions, even though you claim you can do this. BTW, I think you can store waypoints even without GPS satellite reception if I remember correctly. What I asked for could be done on the boat wherever it is with no need to be outside or on the water.
Go to Lowrance and download the PDF version of the HDS8 manual. Then you can search for key phrases like "auto-configure" and you can read what it says then. I did say it was page 104 of the version of the manual that I have (a pdf), implying that yours may be different.
I'm confused if you have a PhD but are stymied by finding a phrase (auto-configure) in a manual that I would consider quite small compared to works routinely accessed by those with considerable education. The index can help, but beyond that, how long would it take to flip about 100 pages and simply LOOK for what I discussed? ...instead of basically whining about it.
Take it to a marine dealer who can do electronics installs.