Trying to hook up the Garmin GPS that came with my 15 RT-Ltd. After many years I put a new battery in the unit. Did a feeble battery charge using my USB from the laptop. Don't know if this is sufficient but the display did come on slightly. After charging overnight I put it on the bike but no display. I don't know if theres a fuse blown nor where the fuse is. Any ideas people? This is not an aftermarket GPS. It was sold with the bike new. TY