I had problems with the radio sound cutting in and out. Tracked the problem to a shorted wire in door wiring boot. Decided to replace the whole harness instead of repair. My first question is that I know initially I have to remove kick panel and parking brake assy. Before I unbolt the P.B. assy do I need to relieve cable tension or can I just unbolt the assy. and let it hang during fix. Any tips would be appreciated.

 

As long as the parking brake is not engaged, just let it hang.

There is no door wiring harness to unplug and replace, the wiring in the door is part of the whole wiring harness, from door lock actuator to door lock actuator and everything in between, headlight switch, multi-function switch,instrument panel, radio, heater controls. It's all one big harness.

You'd be better off trying to find and fix the bad section of wiring.

 

This here! My 2010 had the same issue passenger rear door, it’s a super easy fix....... pull off your door panel, u will see the harness gets pinched with the opening and closing of the door... U can cut out the bad spot and actually pull the harness some to get u some slack where it opens and closes... If I remember correctly, they didn’t leave enough slack in the harness to accommodate the door being used.....

 

I don't mean to sound like a smart a** or anything, but there is actually a "door wiring harness" The reason I know this is because Ford made it to where you have to drop the dash down and un-plug the two plugs on 1998-2009 Rangers and one plug on 2010-2011 Rangers on the LH hand side then you have to remove the three 10 mm bolts holding the E-Brake assembly in place and push it to the side so you can un-hook the rest of it.
But in your defense, I can understand why you thought that you couldn't unplug it because the dash hides them. If you go to most salvage yards they won't even go through the trouble of saving that driver's side door harness because they can't or won't drop the dash down to get the whole door wiring harness.
The passenger side is easy peasy. Ford made it that way so they could add labor cost into replacing the LH door. Ford is scandalous when it comes to making things hard to work on.