Since there are no instructions, I have a truck tore apart and need a few installed photos to guide me. I've spent a hour trying different lines with no clear solution. Please help!
Sounds like you have covered alot of potential options. I would check for interference with other electrical wires that run next to the vss wires from the differential to the abs module (aftermarket fuel pump, lights etc.)
From looking at the schematics it looks like the abs module doesn't...