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I know that many systems in electric cars run on 12v... for example the radio, power seats, power windows. But what about power steering and brakes? When I shut off the car and jump out, there's still some residual ease of turning the wheel which makes me think the power steering is hydraulic (stored energy). But the three orange high voltage leads don't run to power steering pump, so is it 12v? Is there a vacuum booster pump that also runs on 12v?
 

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Most new cars have electric power assisted steering that operates at 12 VDC (my 2009 Chevy Equinox has it). GM developed it for the Pontiac Fiero many years ago. There are no hydraulic pumps for power steering anymore. And the electric motor that assists the steering can do it by remote control, by what features they call as "parking assist" and "lane keeping", which is the beginnings of self-steering. It isn't totally electric or "drive by wire" yet.

Power brakes depend on the vehicle design. Regular gas-engine models only have hydraulic brakes with a vacuum assist from the engine (with large booster behind the master cylinder). Hybrids and electrics have both electrical (regenerative) braking from the electric motors acting as a generator, then the hydraulic brakes with a vacuum assist does the work at lower speeds. So for the Bolt, it has electric assisted power steering and power assisted brakes using a small vacuum pump. They all operate at 12 VDC.

By the way, electric assistance reduce wear and maintenance. If you drive a Bolt EV carefully, you may never have to replace the brake pads as long as you own the EV. As long as cars need hydraulic brakes, we will continue to see the brake fluid reservoir in the front bay.
 

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12/16 build, 2017, white LT
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Great find, GJETSON! The video shows how the pedal displacement is measured by an LVDT, which applies power to an electric motor that drives a leadscrew through a gear reduction to amplify the hydraulic pressure sent to the wheels. No vacuum is involved.
 

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2021 Bolt Premier
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Thanks for the information guys. That Bosch site with it's informational videos reminds me of this: https://www.youtube.com/watch?v=Ac7G7xOG2Ag

I put one of those on my blond-haired son's Big Wheel when he was five years old. I lost sight of him as he rocketed down the street away from me, and I could swear his hair looked red as I lost sight of him. He showed up a moment later, coming up the street in the opposite direction, with an ear-to-ear grin on his four year-old face. :eek:
 
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