It's for the aux lights on the T
the schematic does not show the relay (or the lights) only the connector (which if I recall correctly is itself not correct - think the ground wire is missing- i need to check when I'm at my desktop & can pull it up)
Even though I think all the US bikes have them the two smaller lamps are nevertheless an 'accessory' hence not on the schematic (similar for heated grips etc - only the connector is shown)
Yes - just checked - indeed item 58 it SHOULD also have a ground wire on that connector.
What do you know - looks like the memory is the SECOND thing to go!