Get yourself about 7 inches of a metal hanger. Tape your wire to the hanger on one side depending if your running up or down the boot. I decided to go down.
feed it through the first opening. Then half way in that loom cut a small slit so you can poke the tip through. Do it gently and watch out for the other wires.
Mine went through smooth first try
After that you will be able to reach the end though that middle slit