What is this connector for?

[simplife]

This connector hangs from the wiring harness running along the front bulkhead. For reference it is behind and to the left of the heater pipe and bleed bolt as shown in the photo.

 

[Larry Bastanza]

Looks non-OEM, And my first thought is connected to your battery, for a battery charger system, like a Battery Tender, although it is not a BT brand connector.

Remove the spare tire and follow the wires to see it they connect to the battery terminals.

HTH,
LarryB