The black covering over all the harnesses is actually braided over the harness. It is not something that can be purchased. The complete harness is run through a special machine that braids the covering over the harness. Your best option for repairs does depend on how the repair is made. There is a corrugated split loom covering found at most auto parts stores. Comes in different diameters. What we typically use is a harness cloth tape made by tesa part# 51036. The black does mimic the original covering well. This can be found online at various locations.
The harness itself as a whole is not available. It goes throughout the entire vehicle, so any component change affects the harness. So, it does change revisions a lot. Having stock of each revision makes the replacement harnesses costly. Our recommendation is to repair as needed. If terminals or connectors are needed, we do have them available. Just let us know what you are needing, and we can provide the parts #'s.