That explains why it is unused on most bikes.

 

Well, just was curious what it might be.
Zip tied it up out of sight.

 

could be a battery tender charging lead to hook up a battery tender to. Mine hangs down near the starter.

 

When I bought my street Bob it had the Harley led relocated tag bracket on it. Looked like poop so I replaced it with a lay down bracket. Anyhow while removing it I found it was plugged in to a stock existing terminal under the seat. This could be the connector you speak of.

 

If it has 2 wires with one male (ground) and one female connector (12 VDC) with a matching rubber cover, it is for a battery tender. You can verify by using a volt meter to measure between the pins. It would be ~12 volts with motorcycle ignition turned off - Slightly higher with motor running (~14).

 

What he said ... ^^^^^

 

No,its not battery tender pigtail. It is a 5 pin plug of which it has 4 wires connected to it.