Dead short?

Finally got a bit of time to do some diagnostic on the Dart. I hooked up a tail light in series with the ground cable from the battery and made a new jumper for the ground that fried on the steering column mount. There are two flat, 8 pin connectors that come from the steering column. With both plugged in, or just the larger connector, I get a bright light. With just the smaller plug connected, I get a very dim light. With both un-hooked, the light goes out. I ran out of time between monsoons to get much further.