Crossed wires: Learning the hard way with a 1970 International Scout

automotive rewiring

“It’ll take a few days. A week at most.”

That’s what I told my wife, anyhow, in my effort to convince her that I was qualified to rewire my 1970 International Scout 800A. That proved a grossly generous assumption, I now realize. But at the time I figured I had simplicity on my side, because an old Scout is about as basic as it gets.

My saved Google searches pretty much sum up my qualifications on the subject:

“How to crimp a wire.”
“How to solder.”
“How to make electrical connections.”

A local shop quoted me $2,000 to do the job, which seemed excessive when I could buy a harness for $200, so I figured it was merely a time-consuming process and nothing more. Fortunately, I had a lot of time.

wiring an International Scout
1970 International Scout 800A engine bay

The Scout belonged to my dad before it fell into my care. I was in love with it at a young age, long before I could drive. There was nothing better than sitting in the passenger seat and bouncing down dirt roads. Over the years, Dad took the time and money to make it into a surprisingly civil and pleasant vehicle to drive (if you didn’t need heat, air conditioning, a radio, or a fuel gauge).

I learned to drive stick in it, and the unsynchronized transmission gave it that tractor-for-the-street feel, which demanded patience and skill to work. The old truck just seemed to embody everything I loved about cars—the utilitarian nature, the practicality, and the robust reliability (rust concerns notwithstanding). It seemed built to endure years of neglect, needing only to be fixed with a simple set of tools most of us have in our garages. Rewiring it should have been a cinch, right?

The Scout, like many old trucks, is host to numerous mechanical and electrical quirks. Instead of trying to fix the turn signals, brake lights, fuel tank sender, and the multitude of other electrical connections that rely on a 47-year-old wiring harness, I decided to start from scratch and just replace the whole mess.

My mechanical aptitude, or lack thereof, is balanced ably by my perseverance and persistence. If I take on a project, I will do anything in my power to make sure it’s complete, or that I at least haven’t gone down without a fight. Many of these projects arise out of a combination of wanting to save money and wanting to learn new skills. Thus I found myself standing before the Scout, in the middle of a Michigan winter, in an unheated garage.

The harness arrived in a massive tangle of multi-colored wires and plastic connections. I quickly explained to my wife that I might, maybe just a little bit, be in over my head. She rolled her eyes, the first of a frequent but completely fair assessment she’d unveil during this project.

Sam Brown working on his 1970 International Scout 800A
Sam Brown

I reminded myself that this was a new skill to learn and a great way to save myself $1,800. So I began by photocopying the wiring diagram of the Scout and blowing it up to poster size. My next step was to wrap my head around the phenomenon of electricity, why it goes the way it does, what it needs to get there, what it might need to stop halfway or be turned on and off.

All of my resources and the entire knowledge base of this project were provided entirely for free by generous people much wiser and more patient than I, via the Internet. I scoured web forums, Googled endlessly, and read too many articles to count. With the right amount of patience, it seemed I could rebuild the entire truck simply by browsing 4x4 forums.

The next step was one I had been anxious about: I had to remove the old harness. Most people suggested going about this willy-nilly. I figured I’d be better off to try and keep things intact so I’d have a reference later on. With side cutters in hand, I proceeded to nip, snip and clip my way through the harness. It was in a pathetic state, I discovered, and mice had turned the interior of my dashboard into a respectable studio apartment.

My other concern was the Scout’s abundance of green wires, which International used for 99 percent of the harness. The wires once had small black numbers printed on them, but expecting those numbers to be legible after nearly five decades of neglect is unrealistic. As my clipping and nipping continued, I was amazed at just how well the Scout had run given the terrible state of the harness. Everywhere I looked I found frayed wires and corroded connections, and the whole thing bore the visible scars of previous owners’ attempts to make “repairs.”

rewiring a 1970 International Scout
Sam Brown

With the old wires removed, seeing that pile of gritty and frayed wires next to the Scout was very satisfying. Progress! The satisfaction was short-lived, however, while fear and that pit in your stomach you get when you reach the point of no return started to take over. The Scout was going to sit where it was, dead, until I either hired a truck to tow it away or I finished the project.

I began at the rear, tracing the path of the older wires on the frame through a labyrinth of components caked in grease and mud.

Despite my lack of experience with rewiring, I knew that at the very least, I could keep things tidy, routing wires neatly and keeping everything organized. I insisted on weatherproof connections everywhere, no matter where they were, and heat-shrinking those that were exposed to the elements. And if I failed this project, if I had to watch a tow truck whisk my Scout away to a garage to finish the job, at least I’d know they’d be impressed by my meticulous detail and organization, even if I did everything else wrong.

What followed was a short-lived but savory feeling of accomplishment as I got the taillights, brake lights, and backup lights finished. The dashboard came next, where my illusions of competence vanished in the tangle of circuits, gauges, switches, and doohickeys.

I went back to the Internet to find out what an ammeter was and how it was different from a voltmeter. I found the answer, backed with various opinions on why I should throw it out and replace it with voltmeter. OK, done. Next was my next hold up, the regulator. My Scout had an external regulator, something the instructions that came with my harness made no mention of. To be fair, the instructions didn’t give me much in the way of guidance, or clarity. Come to think of it, I’m not sure why they were even included in the box.

rewiring a 1970 Scout 800A
1970 International Scout 800A wiring

I soon learned that this style of regulator is just generally outdated. One ancillary goal of this rewiring project was to replace any outdated technology that could be swapped with more reliable parts, so in went a modern alternator. As a bonus this required fewer connections, and cleaned up the engine bay.

I was now three weeks and many, many wifely eye rolls into the project I had deemed would take a few days. But progress continued, amidst a lot of cursing and tool-throwing. In the blue haze of fluorescent lights, I resorted to whispering to myself: “Red wire, or was it green? Was that 16-gauge or 20? Left or right headlight?”

For wiring experts, the most time-consuming part of a project like this is terminating the connections. But when you’re a neophyte and make a connection, realize it’s the wrong one, and you’ve routed the wire in the entirely wrong place, your time spent on each connection increases astronomically.

I Googled “grounds” and found out why they mattered and how important they were. I replaced mine, adding three new ground straps and grinding the contact surface to a silver shine.

After 42 days of wrenching, routing, crimping and heating, the harness was in place. Whether or not everything worked was a whole different matter. I checked for a parasitic draw, and sure enough, there was one. After several days of sleuthing, prying, and pleading, I found the light switch I’d installed incorrectly.

The time had come to put it all to the test. I sat in the driver’s seat and slipped the key into the ignition. I pulled the choke, pushed the gas pedal down three times, and then cranked. The engine turned over, enough of a reaction to send my spirits to the moon. But that’s all it did, turn over. Before the project, the Scout was a turn-key truck, and it always started. Replacing the harness shouldn’t have changed that, or so I thought.

I went back through the connections that feed the ignition and the starter. By now, I felt confident around the harness. At the very least, I could call everything by its proper name and function. I pulled the ignition switch, checked fuses, checked fuel, spark, and the battery.

At the end of the day, weary and frustrated, I flicked the light switch in the garage and went inside. The next morning, I checked the distributor. I vaguely remembered pulling off the coil wire that feeds it. Maybe I didn’t plug it back in properly?

I had not plugged it back in properly.

And like that, the Scout roared to life. All I could do was sit and smile and listen to the deep idling growl I love so much.

I now have turn signals, brake lights, and a whole host of creature comforts. More importantly, I now know the Scout inside and out, why it works the way it does, and how to troubleshoot. This project taught me so much more than how to wire an old truck. Resilient and tough as it is, my Scout taught me how I could be the same way in the face of failure.