Painfully. lol I had many cuts on my hand and arm after getting mine in there, 12ga btw so 14 will fit. I just pushed back that black plastic that is behind the e-brake and found the duct to the door with my fingers and then just shoved the wire through. It took a lot of try's to get it completly through and not stuck inside. Once the head got out a little ways I just pulled the rest through from the doors side.
EDIT: If you have the CSII then you could just trace the wires from behind the e-brake and then cut em and connect your new wire to that and pull the new through by the old.