After spending some time sorting out the original wire harness on the 68 F-250, I started leaning heavily towards a new aftermarket harness. This truck needs to be solid for the owner who doesn’t want everything exactly vintage as much as the vintage look with reliability as a focus. With all the cut wires and hacks under the dash and under the hood, we decided to do a few upgrades and focus on keeping it looking original, but making it easier to get working again while also adding some reliability.

I have used the American Autowire kit for my coupe previously and have all the required tools, so I felt pretty comfortable going with them again. The new version is even a little more advanced with some better options around the fuse box. Mostly just little quality of life details and having to only mount one block, etc.

I ordered the AAW Classic Update Kit 510368 from Summit Racing, my old reliable vendor for all general things automotive. I also ordered a wire loom kit for wrapping the bundles and making it look better. I am not a fan of the original electrical tape style, nor do I like a bunch of zip ties. The cloth style split loom wrap is easy to install and access later should a wire need to be accessed. It also looks good under the hood. The main issue I ran into was I like to use just enough loom from a wire to diameter perspective, so the loom is somewhat snug. That means much of my wrapping is on the smaller diameter loom, which quickly got used up. I ordered another 20 feet on Amazon when I got to that point so some of the bundles further from the fuse block got wrapped later in the process.

As before, I started laying it all out and wrapping bundles as I inventoried the branches. Having gone through the original harness and switches, I got some perspective on what was there and what would be unused branches on the new harness. I wrapped as much as I could with it out of the truck, leaving some branches open ended for final assembly. Most of the under dash was terminated so that made for a clean wrap with it out of the truck. I wouldn’t even think of trying to wrap this installed in the dash.

For this application, there are 3 branches that go into the engine compartment. For those, I left them unwrapped at this point and just spooled them up for easier handling until I get the main block under the dash and the fuse box secured.

For the fuse block, the original was screwed to the firewall with machine screws, so there was a couple of bolts attached to the back side of the firewall to facilitate this. I much prefer that over sheet metal screws, like AAW provided, so I did some tinkering to build a plate with risers underneath to accommodate the original plastic risers and try to make a flat mount point over the contours of the firewall pad while also using only the two original screw holes. The original was lightly clocked to the right so I did the same, though once I had it in, I realized I could have made it squared and level since its low enough to clear the left most cluster passthrough in the firewall. I also welded some nuts to the back where the AAW block needed them so I can avoid sheet metal screws all together.

Under dash got started pretty quick with few things in the way. I reused the original clips and routing as much as I could, as well as the original ground screws where I could find them.

Before passing them through the firewall, I wrapped the left and right branches which contain a lot of wires for lights amongst other things. I left the loom shorter knowing I would still be cutting it as I fed wires up to the holes for the headlights as the furthest point.

Since I am going to run out of time before I can get everything installed this week, I went through the AAW installation diagrams and checked off each branch as I connected it to the truck switches and what not. That way, I can go through the checklist when I get home to make sure everything gets connected. I have not yet opened up the headliner to access the bed light or the primary fuel tank sending wire, so I want to make sure I don’t lose track.

As I was going down the list though, I came to the alternator wiring. These originally had a first generation alternator with an external voltage regulator mounted just to the passenger side of the radiator support. Lots of wires going from there to the solenoid and alternator. The recommendation is to go to a 3rd generation alternator (second gen caused some fires and reliability issues). The 3G has an internal voltage regulator and a much simpler wiring requirement. 3G also has a much higher possible amperage output for more electronics like this wire harness enables, should any of that be desired in the future.

The alternator in the truck may have been the original. While it looks clean, it also has the Motorcraft logo on the back. It’s a little crowded on the block, but you can see the wire bundle on the side and leading to the voltage regulator, which all comes out now. I ordered a PA Performance alternator like I have used previously, including the pigtail for adapting to the wire harness, but it wont be here before I head out on my trip, so I will have to finish that once I get home. The new one will be a direct bolt in as well, so no need to change the mounting.

I’m dong my best to preserve the original wiring as much as possible by not cutting it out, but removing it as it went in. I doubt anyone will want it, but I hate to ruin original parts. Though the pile is getting big.

Next, I started down the driver side bundle. The wiper washer pump was one wire so I split that out of the loom. The original harness had a ground going back to the cab, so I need to make a ground wire and probably connect it to the ground in the lights just in front of the washer pump.

Next, I started taking the headlights apart. Taking the front of the lights off was a lot easier than figuring out how to take the whole grill off, so I went with that. Each side has a headlight, directional orange light under it, plus a side marker light. All of that wiring is accessible once the headlight is out. I reused the side marker harness as it was since it disconnected inside the engine compartment and the AAW kit expects it to be reused. Saves some pain removing it and crawling under the fender. The directional can stay in place also, with just a few new connectors attached. The headlight was a bit more involved, but not much.

My bigger problem is a personal aversion to putting rust back on a project like this. The headlight bowls had a good bit of surface rust and I couldn’t miss an opportunity to use the blast cabinet.

Blasted and painted. Still a bit of pitting, but protected for more years to come. I’m not sure why the driver side has a RH on it, but it fit with the driver side of the grill. Will have to see if the passenger side has an LH to deepen the mystery.

New wires are in. Just waiting for new hardware to put the headlight and door back on. The hardware I took off was an assortment of sheet metal screws with 3 different heads, so I opted to put the original style back on for future sanity. They arrive after I leave on my trip, so that will have to wait for another post.

Driver side engine bay branch is done.

Everything from the steering column left is wired in. Mostly heater controls and placing the instrument cluster left for the main cab. Passenger door light and in cab fuel tank need to happen still, but those will wait until I get back.

I have to sort out the courtesy lights still. The style that came with the kit are under dash, like how the Mustang uses. There is a hole in the dash on the far left that I thought had a light in it which I thought might be a courtesy light, but as I think about it, it may be the brake warning light. Either way, a non critical future problem. Phil also brought over the Retrosound stereo, so that is part of the next steps too. Much to do, but this is a good stopping point until I get back.