This is it! Here is where I am going to flex a little bit. You see, every project always has a codpiece, the portion where you stuff and bulge yourself outward for all the world to see how cool and skilled you are. It might be a nonsensically but visually pleasing external design or package. Maybe it’s an overcomplicated or extra shiny piece of machined billet, like it usually was (is?) for me. What I mean is… it’s the part you really saved yourself for, perhaps to the detriment of the project itself.
With Operation IDIocracy, this will be the custom wiring harness that will join the two technological halves of Vantruck: the carbureted, pre-electronic 1986 chassis and cab with the electronically controlled transmission and ECU module of the 1991 donor powertrain.
What I really wanted to avoid with this project is the kind of haphazard point-to-point, ad-hoc, borderline unplanned wiring that plagues a lot of old project cars and hand-me-downs. Example: the Wiring Teratoma of Spool Bus.
I have a habit of calling this “Boomer Wiring” but it is not just limited to an age group where the vast majority of cars really just did need a few wires to run. You’ll often hear “Oh I’m no good with electricity” from a lot of very diverse folks. When I was putting together the FITech EFI system for Vantruck a few years ago, the support groups were full of people saying the kit was bad because of a very obvious (to me, anyway) grounding or power supply issue, or sensitive signal cables draped over ignition coils, or something of the sort. I’m not going to dish on anybody for trying their best if working on something is just plain out of their league or not interesting to them.
But I am willing to take pride in organized, labeled, and purposeful wiring in the interest of future serviceability and replicability. This is what L.E.W.D will be all about. There is going to be a lot of hand wringing about stuffing wires into a plastic slinky.
The Planning
I started thinking about how this was going to work out all the way back before the Stuffening even happened, because the wiring that the E4OD takes isn’t even present on Vantruck’s 1986 chassis. It was clear I’d have to invent a lot of it.
To start Studying The Blade, I decided to go find and buy new-old stock Ford factory wiring diagrams, like a dealership mechanic would have access to. This was fairly simple on eBay and the wider Internets, as there are a lot of classic-focused vendors who scour the planet for these old docs.
I got a 1991 edition, like Snekvan (and Econocrane) were, as well as a 1985 one which was close enough to Vantruck anyways that I could get the gist. I went to a print shop and asked for full-size replica copies to be made, because I was most definitely going to scribble all over these things. The originals were kept in their laminated pouches and bags. Maybe some day I’ll frame them or something!
Next up was getting familiar with how to read these things. Up to this point, I’d only ever researched specific wiring problems on any of the meme vans. This was the first time I had to thoroughly understand what the notation meant and how continuity is expressed between pages and subsystems. I’d designed enough things by now with designated circuit and connector numbers that I got the general idea of it quickly, but of course had to still understand where everything went.
This is a duplicated oil stain from the original document, by the way. A modern wide-format printer made a very faithful replica of someone else’s sweat and tears, maybe over 30 years ago.
I began taking apart the wiring harnesses in Vantruck to find where all these connectors, orange-white not white-orange wires, etc. all were.
As I dug around and probed each circuit to confirm where it lead, I made notes because there’s not nearly enough RAM brain cells to hold all of this at once, and I’d probably overwrite it with a new Vocaloid music video. To make life easy, I tried to replicate the notation used in the drawings.
I also saved the engine bay harness from Snekvan, and took it apart as well to find which wires had to cross over to the dashboard, which had to be spliced or terminated, and which needed to be power supplies or grounds.
I’m starting to get to the point now where the discovery process is done and I have a handle on who has to connect to who. Many circuits had different color designations or numbers, but served the same purpose (fuel gauge, hot-in-run power, temperature gauge, and so on). I just had to find all of them.
With the learned info, I began compiling the master plan. The 1991 harness (“12A581”) will start from the ECU/transmission module and terminate in a set of connectors I define. On the other side, these connectors will join the 1986 dashboard harness (“14401”) which also contained the vehicle functions I won’t change, like the taillights and fuel pump power.
I continued taking apart Vantruck’s wiring inside the dashboard to identify where some of these wires had to meet up. A lot of surgery will happen behind here with gauges and buttons.
There were, of course, some errata that I discovered along the way. Vantruck being an “Incomplete Vehicle” had some wiring which was different than what the diagram suggested, a hybrid of the RV/ambulance integrator package and what a regular commercial van would be. Most of these were worked out in the process of discovery, or I made plans for overriding/starting from scratch.
The Execution
I started simple with the wiring surgery, redoing circuits that had one pin or one wire so I could test drive my process.
I chose Weather-pack connectors because they’re generic and plentiful and I wasn’t pressed for space or needed a tiny pitch. On each side of the connector, the circuit number was labeled, and the connector itself got a number as well.
The numbers were tracked in my notebook showing where everything went. I kept the notation of the Ford diagrams for all work, including hard splices and outright replacement segments. For instance, “HISR” for Hot in Start and Run, as well as the color names (R-Br is Red with a Brown stripe).
The main vehicle interface connector where these two harnesses meet will comprise two six-pin Weather-packs carrying common functions. The new combined engine and dashboard wiring harness I bestowed the part number 69A420. All of my connector designations and splice codes begin with 9000, and subsequently go Over 9000.
The chase is on. I ordered a round of 16 gauge colorful automotive wire in the number of colors and pins I needed.
Here, I’m stuffing a loom with the wires that will be needed in the dashboard. Yes, I was trying to find Miku Blue wire loom. No, nobody sells any, just a plain light blue. Yes, China could manufacture it for me. But I’d have to buy a minimum of 2 kilometers of each size I wanted. I wasn’t in the mood to own several pallets of Miku Blue wire loom spools.
Maybe the next van.
When one end was under control, I stuffed the bundle through the existing firewall bushing.
Wiring commenced on the dashboard end of things first. I used crimp-and-shrink weatherproof splices in all of the joints. No vampire clips/quick splices for me! Observe all of the circuits labeled as I was progressing.
On the other end, I prepared the ECU/TCU harness using Snekvan’s salvaged connector and wire bundle. Wires I did not need were excised close to the big connector to keep things cleaner. They were left as heat-shrunk stumps in case I had to re-use them for something.
In the 1988+ electronic transmission vans, the ECU/TCU was kept in a little pocket inside the cabin underneath the HVAC blower motor, with the large connector pointing into the engine bay.
In comparison, Vantruck just had a small bushing hole with wires that served the blower motor and some other HVAC utilities. I designed and 3D printed using TPU a bushing that would envelop the new bundle and snap into the cutout.
This worked out pretty well! It’s a pretty tight squeeze to get everything clicked in.
The transmission controller sits perfunctorily upon the lid of the blower motor, just zipped in with Plastite screws in a 3D printed bracket set. Nope, no fancy housing for you. If the transmission ever misbehaves, I’m sure a swift kick here would resolve it.
In the middle, it was time to make the worlds collide. This obviously looks like more of a nightmare than it was because of all the extra wire I left just in case.
After a night of furious crimping, it somehow looks….. intentional. Almost artisanal and bespoke.
Back on the inside, I hooked up some Important Buttons. Most importantly, the E4OD has a combination light and button that serves as an overdrive lockout, like if you’re towing or gently engine braking down a hill. I figured out the circuit that this takes, and ordered a handful of what I call Formlabs Buttons (as the first time I saw them extensively used on a product was on their 3D printers).
The LED ring on the Overdrive Disable button is hooked up to the transmission controller circuit designated for it. It’s actually used as a diagnostic light as well, for some basic pre-OBD error state divination. The other button powers the Dongle of Diesel Distribution and activates the solenoid valve if I need to prime most of the fuel system quickly.
One of the last little kibbles to add here was a new vacuum warning switch. The OEM one that came with Snekvan had rusted entirely through, which explained why the BRAKE warning light was always on… as it wasn’t sensing any vacuum level.
This is an aftermarket one designed for retrofitted power vacuum brake boosters. It closes its circuit when it detects a low vacuum level (such as when power brakes have been used) and you’re supposed to use it to throw a relay and activate an electric vacuum pump. The IDI already has the belt-driven vacuum pump, so this thing just activates the warning light circuit.
It sits right here next to the “Vacuum Log”, with one end capped off and a short hose to the rest of the system.
One of the last actions in the engine bay was to mount the new glow plug controller. I standardized the bracket I made for Econocrane and also added an extra leaf for the turbo oil bilge pump.
The glow plug wiring is now all installed as well. A feeder line drops from the new 69A420 harness to power the bilge pump whenever the key is in Run.
Editor’s Note: This little pump ended up not being enough on its own to pull the oil out of the turbos, so the Multibracket sits empty as of today. Currently, there is one of them per turbo, mounted underneath the cab. As for how I got away with it for Snekvan’s original integration? I have no idea.
It’s time to test everything! With the key in Run, it…. well, immediately railed my power supply because the glow plug circuit tried to turn on and draw 300 amps. I ran this first test with my lab power supply to prevent OOPSIES and also to get an idea of how many amps all of the little subsystems want.
With the glow plug controller disconnected, I was able to verify the functionality of a lot of things. The fuel gauge was “working”, for one. The transmission responds to the button press, and my purge solenoid clicks. Note that this wasn’t done with the engine booted up, just in “Run” position. And most importantly, I was able to click the starter in and out. So far, it seemed like the L.E.W.D was a success. The real test will come soon when the first light-off occurs.
Let me be very very clear here: this is a unitized, condensed writeup that encompasses the single longest and most brain-scratching subtask of all of IDIocracy. This was not done in a night, or even a week. I’d say I started reading the diagrams and drawing stuff up all the way in January, and once the little mechanical side quests were done, basically all of March 2023 and some of April was spent on this alone. The balance was just tidying things up and adding the final details like the exhaust before I was able to break the Lawson Barrier and achieve first ignition. In comparison, even fabricating the turbo pipes was just a day or so.
That’s why I said at the beginning: This wiring is my project flex, forget the small flying private freight train it’s attached to.
Heavy Power
Much simpler in comparison, just bigger, was my new battery wiring. I was planning to move to a single large battery like a Group 31 in lieu of the dual batteries of the OEM setup, which occupied approximately 109% of the space in the van engine cave.
Putting this thing in was a good chance to start completely from scratch with clean wires and connectors. Nothing was reused besides the positive starter cable rubber bushing.
The new cables are made from 2/0 flexible welding cable with giant hex-crimped lugs on the ends.
On the other side are some solid brass terminals that were also hex crimped. All of the ends were sealed with adhesive-lined heat shrink, and I also ordered red wire loom to bundle all of the positive feeders together.
The yellow wires are the original power jumpers for the glow plug circuit that I crimp-and-shrink spliced into custom 8 gauge feeders coming from the starter solenoid.
So why was my test battery on chunks of wood 4x4s? I was testing the underhood clearance and getting lengths needed for the cables, but that will be close to their its final height after a modification of the battery tray. Stay tuned for next week’s episode to find out why!
