Most electical issues for me is like trying to do quantum physics, I just don't have to skill to work w/ it. I can follow directions better than the average bear, so I'll try to soldering iron in the morning when I get home from the station.
On a side note, I noticed that the intaller at Best Buy extended the ground wire comming out of the D3. I'm assuming for the amp I have in the trunk, but I'm not 100% sure. Could it be a bad ground causing the problem or would the HU not work at alll if it was?