After burrowing through many threads after this info, I got a mix of folks saying left side midway down the seat, some said right side. The drawing shows the GPS2 connection as the end of the rear harness, right side. After finishing my GPS install, I thought I'd post a pic showing the connector.2018 RTL GPS_Accy 12 VDC Connection.jpg . It's on the right side, near the gas tank ground bolt, towards the middle. This picture has my GPS harness attached, the connector is just to the side of the BRP on the visible label.

So I'm using an old Zumo 550 until I can afford a new one, all I needed was 12 volts keyed. The BRP plug was a AMP Superseal 1.5. I bought a bag of pigtails here; https://www.ebay.com/itm/5-Kit-2-Pin...72.m2749.l2649 . The only problem I had was the black and red were crossed on the pigtail, when plugged in to the Spyder the black was hot. Heat shrink covered that up, so no big deal.

So that's another one for the books. Maybe it'll help someone else at some point in time.