What does the dark blue wire coming out of the firewall for the light harness go too? I know there is a blue running from the alt to the voltage regulator however thats a different wire (that I now have connected to the brown since I have an internal alt.).

Dark blue and light blue are the turn signals, I forget which is which.

Excellent, thanks!

Could also be for the oil pressure light.

I believe its the oil pressure lite...if you have console guages...the wire colour I think is brown...been 2 years since I did my harness....

oil pressure light sender wire is in the engine harness, not the light harness.