You can fish the power wire through one of the grommets on the firewall and then tuck it under the plastic molding all the way to the trunk. It's a tight fit in the grommet but it can be done. If I remember right, when I did it I used a piece of stiff metal coat hanger, stuck it through the grommet from the inside and then electrical taped the power wire to it (super tight) and pulled it through.