I recently crossed a milestone on my current restoration project. I have every last wire free from the body of the vehicle. I’d pulled a number of smaller wiring harnesses from Project Sunny, my 1993 Range Rover, but one harness had eluded me.
Packed up under the dashboard was the main harness, a tangled spaghetti monster with what looked to be a couple dozen smaller branches shooting off it in every direction. A thick knot of multi-color vinyl-wrapped copper greet me, festooned with countless relays and fuses.
Everything else about this generation of Range Rover is unnecessarily complicated, so why wouldn’t the electrical system? After all, there are no jokes about British wiring, just unfortunately true stories. To be fair, this vehicle was the epitome of luxury at a time before microprocessors and automotive CAN-BUS networks. Everything seems to have a relay and definitely a fuse.
For weeks I went out to the truck and looked at this last section of wiring harness, knowing full well that it had to come out. After all, it holds the sound insulation in place. And that needed to come out so I could repair the rusted-out floor panels underneath. But it resembled the roots of a tree that had grown in place over craggy rocks and around fence posts. It emanated from within, apparently, rather than having been installed into the truck’s body.
In the end, I had to remove the steering column support bracket. There was simply no way the endless wires, brackets, relays, and other devices attached to it could be fed through the impossibly narrow spaces they occupied. With that section removed, the last of the wiring was finally out of the way.
I pulled the remaining wiring free from the interior. Then I wondered to myself, “Damn, how much wiring is actually in this thing?” My best guess was that lone harness was good for 60 pounds by itself. And that wasn’t counting the sub-harnesses for the front clip, the engine, the rear body, or the ones that run up the A-pillars and back through the roof.
It turns out, not as much as I’d predicted. All told, I weighed about 54 pounds of wiring. But now I know. And so do you.
@John Roncallo, sounds like a cool project. I can only imagine what that harness weighed.
18 years ago, I put a Mercedes M120 V12 engine into a 560SL. The engine came out of a 1996 SL600. The engine harness with a few other accessories bundled with it fit into one of those bins you have. All the other body harnesses fit into another bin just like it. I should have weighed them at the time.
I spent 6 years in the USAF in an avionics maintainer career. The wiring for everything was all the same color (white). When the aircraft were new, they had numbered sleeves installed but over the years they were sometimes lost. Our best tool was the ohm meter. On top of that there were several voltages like 24 vdc and 120vac which was also 120hz, if you got zapped by that it was like lightening going through you. This fact I know from experience! You would be amazed at how much wiring is in an aircraft and so neatly bundled and tied with string, no zip ties.
Wiring is a factor in many applications. Missiles, planes, boats cars and many others. If and when you wanted to remove the factory wiring and opt for a replacement, there are number of issues to consider:
Size of the wires – designed to carry the “workload” required by the circuit. If it’s 18 guage wire in the old harness, it needs to be 18 guage in the new stuff. The copper itself is the big weight factor.
Insulation – with modern motors running at higher temperatures, newer materials were required. Over the past 100+ years, insulation has gone from braided fabric to vinyl to crosslinked materials (polyethylene) and even to Teflon (registered trademark of DuPont). Newer materials are thinner and thus lighter.
Options – in the glorious days of the 60’s and on, almost every car had the same wire harness. That harness was made as a standardized unit for installation in the same model, regardless of the options that were put into the car. One car might not have air conditioning but the wiring was still in the car. Same with radio options, speakers, and any/all other electric devices.
Safety – wiring was routed in such a fashion that consumer safety was a top priority. You couldn’t have wiring in a car or plane that would be subject to vibration. That might give way to an electric failure causing harm to some degree.