Alternator started sparking

I tested my connections and found that I did a poor job rewiring the blue wire. I’m getting power to the MSD box again. I still have the .3 loss with direct connection. When I unplug the blue ignition on wire, the loss goes away. I took apart the steering column and checked out the wiring a while back and it looked fine. Where could this gremlin be hiding? Another possible clue... When I turn the lights on with the engine off, there’s a big drop on the ammeter gauge. All lights work, but the driver side front marker light is out.