The part that is missing is only the switch. This switch (which is operated by the side stand being either up or down) energises the relay. It puts the positive that's flowing through the relay to earth, and thus completes the circuit. The two wires that are twisted together is the relay positive being put permanently to earth, so the relay is energised all the time, just as it would be if the side stand was up. It's the relay that does all the "thinking", so it acts as though the stand is up, whether it is or not. When you mentioned the neutral light being on or off - the common factor is the relay itself. That's what leads me to believe that this may be where the fault lies. It could be a blocking diode that's failed (allowing current to flow both ways) or anything else. I'll try to do a drawing of the circuit, to explain it to you, and post it as soon as I can. In the meantime, I,m sorry to say that I don't know exactly where the relay is situated, but keep looking for where the two wires go, and I'm sure you'll find it.
