1972 C10 underhood wiring help

[Willshook]

Trying to get the wiring sorted on this 72 - have some wires I can't figure out what they do. The first picture is on the firewall, second is inside the cab. I've been looking hard at the wiring diagram and just stuck on a few wires.

The big red wire with the yellow connector looks like it goes to the ignition unfused in the fuse block, and I don't need that so I'm going to pull it out.

Not seeing the brown-white cross connect, but I see it's circuit 141 for the "TCS SOL"? What is that?

Not sure what the blue and black wires are - they are taped off so maybe not needed anymore

Thank you for your help!