Well trace the wires to the rear electrical box and it should have little clips that hold it together, press them in and open the box. There are caps around the wire where it goes into the box that seal the water out you will have to unscrew to slide the wires through. The wires should be held on the coil with nuts. Now have you tried to pull the boots back and clip the wire a 1/4 inch or so and re install the boot? Try that before you replace the whole wire first.