Made some progress yesterday on the wire harness install.
For the actual harness itself, I decided to use one made by Rebel Wiring. Like any of the harnesses available, they have some good points and they have some bad points.
The panel itself is constructed from using off the shelf components. While this may not look as appealing as a purposely molded panel, it does offer some benefits. Since the components are readily available, it's quite easy to add additional circuits in the future.
I also like how the wires are terminated at the panel. While this does have the potential to get out of control, especially if you start cutting the supplied zip ties, I think it ultimately makes for a cleaner install.
The one thing that I do not like is how far the wires stick out the back of panel. If you try and bolt it down using the existing holes, it places quite a bit of strain on the fuse holders as well as the wires. To overcome this, I ended up 3D printing a mount that has a built in wire way.
As supplied, the harness has four main wire groups. This probably works out well for most cars, but for these trucks, they only need to have two main runs....essentially, everything inside the cab and everything outside the cab. So, even though they tell you not to cut the zip ties in the instructions....that is exactly what you have to do.
I started off by screwing the harness and mount to the work bench. With it mounted solid, you can pull all of the wires taught as you begin to reorganize them.
The trick is to go nice and slowly and keep the wires halfway organized. I end up going through a ton of zip ties during this stage.
After a little bit of a spaghetti mess, you end up with this...
With the panel mounted to the firewall, you can get a sense of where the wires need to run. The wire bundle running along the kick panel will be eventually moved up out of the way.