This is Tad's dad. Couple additions to add. The rubber convoluted section had to be cut to get access to do soldering and heat shrink. To get heat shrink far away enough to not get it to shrink in the wrong place from the heat needed to solder, you need a few inches of wire to slide the heat shrink away. The black defrost wire was broken very close to the bottom grommet. We probably didn't need to undo the bottom grommet, but didn't know it wouldn't help and we thought we could just slide everything up. That bottom grommet was almost impossible to get back on and we struggled with it longer than it took to do the soldering. The original wires may have been too short and stressed from opening and closing the trunk many times. We added an inch to each broken wire. We used 3M 33+ tape to wrap the wire bundle so it flexes as a single unit. The top grommet had to be zip tied because we cut it. The cut along the convoluted part was filled with ultra black rtv and we're letting it set 24 hours.
Any electrical malfunction in the trunk is most likely due to broken wires in the convoluted section. When you can't figure out why the lighting, defrost, or the spoiler won't work, this is where to look.