LAKE ORION TOWNSHIP, Mich. — In a nondescript supplier park in suburban Detroit, an electric vehicle startup backed by Amazon founder Jeff Bezos is building what it hopes will be America’s newest automaker.

The facility is filled with dozens of prototypes, crash-tested vehicles, a crude lab vehicle skeleton adorned with wires and, most importantly, a busy “beta” assembly line that has been building electric vehicles since December for the startup, Slate Auto.

Slate is using the location — a stone’s throw away from a massive General Motors assembly plant — to produce more than 70 vehicles for internal testing, certification and everything else a company needs to prepare to produce and sell vehicles in the United States.

The beta production line features roughly a dozen labeled stations for things such as the vehicle’s doors, tailgate and front ends that sit in bins or on surface areas made out of wood and steel parts.

Employees move back and forth between the bins, tables and assembly line as songs such as Whitney Houston’s “Saving All My Love for You” and Pat Benatar’s “Love is a Battlefield” echo throughout the lively facility.

The largely hand-built vehicles being made are bare-bones, two-seat, two-door electric pickup trucks that can also be converted to different body styles of SUVs, such as a five-seat fastback or into a squared-off look like a Jeep Wrangler.

The vehicles have injected-molded composite exteriors, crank windows, no infotainment systems and a litany of do-it yourself options. The plan is for every vehicle coming off the line to be the same to reduce complexity, before adding any additional features or different covers/tops.

Auto executives have tossed around the idea for such a modular, stripped-down vehicle amid the rise of connectivity and affordability concerns, but so far the challenges have outweighed the potential opportunities, or companies have struggled to keep prices down.

Slate believes it can succeed where others have failed through simplified manufacturing and lower costs – two areas where other EV startups have failed in recent years.

“This one’s going to be different for a number of reasons,” Eric Keipper, an auto veteran and Slate’s head of engineering, told CNBC after a tour of the company’s manufacturing facility. “We took the back-to-basics, only-the-essentials approach, and, really, we’re building a completely new category of product.”

Slate exited its “stealth mode” in late April by revealing its first vehicles — several two-door electric pickup trucks and converted SUVs — that it expects to begin deliveries of by the end of next year. It’s in the process of building out a full production facility at a former printing plant in Warsaw, Indiana,…