Coil voltage

Thanks for the replies, Sorry, I have been away for a few days. I am getting 12.7 V from the battery to the bulkhead connector. I am only getting 10.3 V to the ballast. The ballast is bypassed, and I am only getting 10.3 V at the coil. I have not checked voltage under the dash as of yet. Wiring definitely is not my specialty, so if anyone knows where to start, that would be appreciated. Could the bulkhead connection itself be causing the problem? Possibly ignition switch wiring? Wiring from alternator? I am assuming the factory wire to the ballast should be getting 12 V , and bypassed I should be getting 12v at the coil.