looking to add a low powered winch into the trunk of my 2014 outlander sport and need to get 12v 15amp connection somewhere into the trunk. should i run a whole set of new wires from the battery/fuse box or is there already auxiliary power back there i can tap into?

 

If it was me , yes run some correctly rated wiring direct from battery and including its own separate fuse ,then if a fault should occur you will only loose that item in the circuit. Any other wiring will have other items running off it.