Rivian and TE Connectivity strip the wiring myth bare

For most of automotive history, the wiring harness was considered the vehicle's plumbing. Nobody designed a vehicle around it, and nobody bragged about it in a shareholder presentation. But that indifference is now a veritable liability. Centralised compute, zonal electrical architecture, 800-volt power systems (and even lower), and high-speed in-vehicle networks all converge on the same tangle of copper, aluminium and connectors - and if that tangle cannot be built at volume, on a Tuesday, on a moving line, a few hundred thousand times a year, none of the rest of the roadmap matters.

That was the starting premise of an AMS livestream, "From Architecture to Assembly, Industrialising the EE Backbone of the Software-Defined Vehicle," which paired an OEM defining the architecture with a supplier building the parts that either enable it or stealthily cap what it can do.

Dmitry Fudym, Principal EDS Engineer and Manager at Rivian, sat opposite Bernard Vetten, Senior Principal Field Application Engineer at TE Connectivity, and between them the conversation moved from harness geometry to thermal physics without once losing its practical edge.

Where the miles actually went

Rivian has been more willing than most OEMs to publish numbers, and the R2's are striking. Its zonal architecture reportedly removed 2.3 miles of in-line wire harness length and cut high-voltage cabling by 70 percent against the outgoing approach - and all this on top of the 1.6 miles and 44 pounds already stripped out between Gen 1 and Gen 2 of the R1.

Asked where those savings came from, Fudym pointed first to the reduction from 17 ECUs to seven and to what Rivian calls its powerhouse module, which consolidates five components into one. But he was clear the real driver sat further upstream.

"What we can talk about is some high-level goals to start with. For my team, for R2 design, we said we do not see a need for this many inline connectors, at least not the inline connectors between main harness families," he said. "We created that goal because we said every line, every inline connector needs to earn its place, needs to provide value."

That meant deciding, early and deliberately, which harness families would connect directly to which zone controller, before the vehicle's build sequence made that decision for them. On the R2's A-pillars, five separate harnesses now converge on a single zone controller on each side, eliminating a web of inline connections that would once have run between them.

Vetten, whose company supplies both high-voltage and high-speed connector families into exactly these architectures, added context to the Rivian numbers.

"One thing to keep in mind, of course," he said, "is that we are talking about different functions being delivered. You have a higher-feature vehicle versus a lower-feature vehicle," before agreeing that zonal implementation "definitely is enabling quite a lot of cable reduction," provided harnessing is considered "at an early stage very much."

"Complexity" does not disappear, it moves house

Rather than eliminate complexity, zonal consolidation relocates it. Fudym described the shift plainly. "The complexity - if you want to call it that - we shifted effectively into the zonal controllers," he said. That has organisational consequences as much as technical ones. Harness and systems engineers, he argued, need "a seat at the table" during early architecture discussions, not after decisions affecting harness cost and mass have already been locked in. Rivian's vertical integration, he said, made that natural rather than exceptional.

Vetten agreed, framing the trade-off as one of control rather than elimination. Vertically integrated OEMs that keep zonal ECU development in-house shorten the communication chain with Tier 1 suppliers considerably, he noted, which speeds up the changes that ripple through a zonal system.

The risk, in both their views, is treating harnessing as an afterthought once the power budget or signal count inside a controller turns out to be short.

Fudym's preferred image for architecture reuse across platforms, R2 shares its underpinnings with the forthcoming R3, was geological rather than electrical. "The way we think about it is to treat the zonal architecture like one of the monuments," he said. "A battery pack is a monument. An HVAC module is a monument. Drive units - once those are set in place, they are not moving. They are stones. They are monuments." Vetten later extended the metaphor to the high-compute module itself, whose liquid-cooling requirements are increasingly fixing its location in the vehicle just as firmly.

The voltage question is really a clearance question

On the industry's drift towards 800-volt and higher architectures, Vetten located the real design pressure not in insulation or thermal management individually but in creepage and clearance requirements under IEC 60664, and specifically in the comparative tracking index of the materials chosen. Higher pollution-degree environments demand more clearance and larger connectors, precisely what nobody building a zonal system wants. "One of the main benefits of going to higher voltage is actually reducing copper and/or aluminium. You do not want to win at one spot, reducing some of your metal usage, but then increase your plastic because you have to space out these connectors and these terminals quite a lot more," he said.

Watch the full livestream

From Architecture to Assembly: Industrialising the E/E Backbone of the Software-Defined Vehicle

Every OEM roadmap now assumes centralised compute, zonal E/E architecture, 800V electrification and high-speed in-vehicle data networks.

Rivian, notably, has stayed close to 450 volts through both R1 Gen 2 and R2, a decision Fudym defended on integration grounds rather than headline voltage. Folding the onboard charger, DC-DC converter and a zonal controller into the powerhouse module, mounted directly on the battery pack, let Rivian use shorter, unshielded internal cabling and select aluminium where it saved mass, independent of whether the system ultimately runs at 400, 800 or 900 volts. "It is not just 400 versus 800," he said.

"You have to push on what is out there." Asked directly what would change first if Rivian did move to 800 volts, he pointed to supplier qualification ahead of insulation or cooling, specifically finding partners comfortable working across both copper and aluminium, and both crimping and sonic welding, as copper costs continue to climb.

Small housings, large tolerances

Packing optical and high-frequency data connectors alongside power and signal in shrinking housings has tightened manufacturing tolerances on both sides of the supply chain, Vetten said. An air gap between mating halves that would be irrelevant on a power connector is enough to degrade a high-speed data signal, at rates now reaching 12 and 25 gigabits per second, which is why higher-speed leads increasingly come from dedicated harness makers rather than general assembly.

Validation now runs across the full automotive temperature band, from around minus 30 or minus 40 degrees Celsius up to 105 or 125 degrees, cycled repeatedly rather than tested once. "You would be surprised how warm a vehicle can get just on top of the roof standing in the full sun for quite a while, and how cold of a climate we have around the globe," Vetten said.

Automation follows design, not the other way round

Fudym's team is building what he called "a very narrow AI-supported tool," used in-house to automate circuit-level temperature validation and other standard checks, freeing design release engineers for higher-impact decisions, with change management, a notoriously difficult problem in harness engineering, built in from the start.

But both guests resisted the idea that automation itself is the industry's binding constraint. Vetten warned that proliferating trim-level variation, rather than any single technology gap, is what makes automated harness assembly hard to justify. Fudym went further, arguing that design for automation, a phrase Vetten also used moments later, has to start when vehicle structure is still being defined, not after.

Asked by Vijay Koshi, Senior Director of Engineering at Molex, how realistic fully lights-out harness and assembly plants are, both were candid. "I think it is not in the near-term future," Vetten said, though he described the industry as assembling the "building blocks" that could eventually get it there.

Responding to Paul Booth, Electrical Engineering Manager at Wrightbus, on the risks of moving from multiplex to zonal architecture with limited prior exposure, Vetten pointed to a "proven track record" already established in production vehicles, while Fudym's advice was characteristically direct.  "Do not settle for lower-level goals," he said. "Maybe start with one zone, and that is okay. Consolidate two controllers into one; start with that, three to one, whatever it takes. That is a step in the right direction."