I'm guessing it is supposed to be soldered to the empty lug on the pot right next to it (looks like a blend pot the way it's looks to be wired), the one with the cold solder on it. That being said, I'm not real impressed with the soldering "skills" of the person that soldered those solder joints...cold solder joints and burnt insulation. I have three Sires and never looked at the soldering work in the control cavities...perhaps I don't want to but after seeing this, I probably should. If it looked like that, I would tear it down and rewire/resolder all of it. It's a failure just waiting to happen (or has happened).