the ballast connectors on the harness have locating pins on them. sometimes they get broken off and its possible to put one on upside down. just make sure they are plugged into the ballast the correct way. dont ask me how i know LOL
also, make sure the Ignition box and the Voltage Regulator are thoroughly grounded to the body. the bolts that mount them are the ground, so you want good contact between the cases and the body. dont forget all your other grounds, battery to block to body