Battery not charging?

[Mechdawg]

Hey all, The voltage at my battery with the engine running is only reading 12.5 volts so Im pretty sure its not charging. I had the alternator tested at autozone and it checked good. So now Im thinking voltage regulator. I did the mod to install a guage panel from an idiot light panel and the brown wire that runs from the old gen light to the voltage regulator gets cut off. So I was wondering if I did that wrong does it need to be connected to something still if so what? I was reading the conversion FAQ about going to an internally regulated alternator but it requires you to jumper the blue and brown wire together but like I said because of the gauge mod my brown wire is cut off by the guage connector. Sorry for the long post but Im stumped thinking I missed somthing.

When doing the panel mod I did run a new wire to the battery block and another one to the main pos feed on the alternator just like it says on GMC pauls never really said what to do with the old brown gen lamp wire though.

Thanks for any help all
Tim