Fun Navigation Wiring Mystery

[bobman21]

Hey guys -- I'm new here and don't have an E53 BUT I have an E39 and have the same nav/headunit. I heard nobody knows the nav wiring like the guys on this form us so here's to hoping you guys know what's going on..

Here's the problem: Video

Background:

- One of the POs took the stock car and wired in satellite radio and perhaps other mods (new head unit?) that I don't have any history about.
- PO who sold it to me had done the rewiring back to stock but evidently it wasn't right.
- All systems appear to be working properly (e.g. MPG calculation, DSP, radio, etc.)

What I've tested:

1. I put in a different, working head unit and there was no change to the signal.
2. It had an MKIII which I upgraded to an MKIV. It changed the signal (travels up more slowly now than it did before) but nothing fundamental about the shifted x-axis or the traveling y-axis.
3. I resoldered what I believe are the x/y axis coaxial lines going from the blue connector in the navigation to the head unit. These had previously been cut and re-crimped, probably with some signal leak into the coaxial ground sheath. But even after properly separating the signal/ground and insulating the wires, the signal didn't improve.
4. Not so much a test, but the WDS weren't very helpful because (as far as I could tell) they just show how things are wired, not the individual wires for all the connectors and the pin diagrams (correct me if I'm wrong).

Thoughts? Much appreciated!