I have the same wires and connector on a 2008 model, but mine are connected.
The wire coming from down below /aft is active when the nav instruments are switched on at the switch panel.
The switch in the panel just activates a 25A relay under the bed
in the port aft cabin
which feeds the autopilot
I can only speculate as I don't have any tool here to trace the wires:
My take is that this wire runs back to the nav area so that larger consumers (chartplotters, radar
processors, etc) can be connected to the same relay.
If you want to know for sure: these RF tools described by A64Pilot work
quite well and cost only around 10 bucks on ebay (shipping on the slow boat from china
If you want to lift
out for winter: Sant Carles boatyard is filling up quickly, our 380 is already on the dry!