Common sense troubleshooting time.
1) B+ is 11 volts at unit? disconnect the wire from unit and see if you then get 12.5 volts. Is your voltmeter accurate? Connect it to your battery terminals to see if you get 12.5 minimum voltage - if you do then it is good.
2) B+ of 2 volts on a ground? Disconnect battery and using ohm meter meter your grounds. If it is ground - you cannot have B+ of 2 volts. Suspect bad solder joint or bad ground connection ( could be open ground in computer)
3) Where voltages are lower than should be "For some reason I'm getting 2+ volts to the brown/blue when hooked to ground. Weird? Should be only (-), right? Red/black to body I get 11+, Red/black to Brown/blue I get 8+ volts" cut the wires and see if the voltage goes up - isolate what is pulling the voltage down. If all roads lead to the computer then------ otherwise you could find a bad solder joint, a bad crimp joint - anything. If you take a deep breath and look at ONE circuit at a time and follow it through - you should be able to diagnose it. Without a schematic diagram with voltages marked as a roadmap though - it may be impossible. Patience & Logic Patience & Logic - helped me many times. Just had a case on my son's car - alternator went dead. Checked at battery got 11.2 volts with motor running or not. Tried charging battery - overheated charger - battery had internal short. Put in new battery and alternator - voltage at battery now 12.56 volts car running or not. Scratched head thought it through. Checked voltage at alternator with car running 14.6 volts. The battery melted the wire open from the alternator inside the harness. Put in new wire -problem solved. Don't get frustrated - think it through - I'll bet you will find it.