What electric power steering conversion means and why people do it

Electric power steering conversion is the process of replacing a hydraulic power steering system with an electric one. Hydraulic systems use fluid pressure driven by an engine belt; electric systems use an electric motor attached to the steering column or rack. The conversion involves removing the hydraulic pump, hoses, and fluid reservoir, then installing an electric motor, a control module, and new wiring.

People convert to electric power steering for several reasons. Electric systems use less engine power, which can improve fuel economy slightly. They also eliminate the risk of hydraulic fluid leaks, reduce maintenance (no fluid changes or pump repairs), and allow for features like lane-keeping information or steer-by-wire in newer vehicles. Some people convert older vehicles to electric steering to make them easier to drive or to prepare them for future autonomous features.

The conversion is not a straightforward bolt-on job. It requires mechanical work, electrical knowledge, and often custom fabrication. The cost and complexity depend on your vehicle's year, make, and model, and whether you are starting from a car that already has some electric steering components.

Key Takeaways

  • Electric power steering uses an electric motor instead of a hydraulic pump, eliminating fluid leaks and reducing engine load.
  • A full conversion requires removing the hydraulic system and installing an electric motor, control module, wiring, and often a new steering column or rack.
  • The work involves both mechanical and electrical tasks; many people hire a shop experienced with steering systems rather than attempting it alone.
  • Cost varies widely depending on the vehicle and whether you use a kit or custom parts, typically ranging from several hundred to several thousand dollars.
  • Electric steering systems require a reliable power supply and proper grounding, so electrical work must be done carefully to avoid steering failure.

The main components you will install or replace

The heart of the conversion is the electric motor, which does the work the hydraulic pump used to do. This motor is usually mounted on the steering column (column-information) or on the steering rack itself (rack-information). Column-information is simpler to retrofit onto older vehicles; rack-information is more common in modern cars and provides better steering feel.

You will also need a control module or electronic control unit (ECU). This is a computer that reads signals from the steering wheel angle sensor and decides how much power the motor should provide. It communicates with your vehicle's existing systems and may need to be programmed to work with your specific car.

The steering angle sensor tells the control module which direction and how far you are turning the wheel. If your vehicle does not already have one, you will need to install it on the steering column. You will also need new wiring to connect the motor, sensor, and control module to your vehicle's battery and ground points. Many conversions require a separate relay and fuse to protect the electrical circuit.

Finally, you may need to replace the steering column or rack itself if the electric motor cannot be mounted on your existing one. This is often the most expensive and time-consuming part of the job.

Mechanical steps in a typical conversion

The first step is to disconnect the battery and drain the hydraulic fluid from the power steering system. You will then remove the hydraulic pump (usually belt-driven from the engine), the hoses, and the fluid reservoir. This frees up space and weight from the engine bay.

Next, you remove the steering column or rack, depending on which type of electric information you are installing. If you are doing a column-information conversion, you may be able to keep your existing column and bolt the electric motor to it. If you are doing a rack-information conversion, the work is more involved because the motor must be integrated into or mounted directly on the steering rack.

Once the motor is in place, you install the steering angle sensor on the column. You then bolt everything back together, making sure the motor and sensor are aligned correctly. Misalignment can cause the steering to feel off-center or to fight you when you turn.

Finally, you test the mechanical fit: turn the wheel lock to lock and make sure nothing binds or rubs. The motor should move freely, and the steering should feel smooth before you add any electrical power.

Electrical work and wiring the system

Once the mechanical work is done, you run power and signal wires from the battery to the control module, motor, and sensor. The power wire should be as short and direct as possible and must include a fuse rated for the motor's current draw. A typical electric power steering motor draws 10 to 50 amps depending on the system, so the fuse and wire gauge must be sized correctly to avoid fire risk.

The ground wire is equally important. A poor ground connection can cause the control module to malfunction or the motor to behave erratically. Many people run a dedicated ground wire from the motor and control module directly to the negative battery terminal or to a solid metal point on the frame.

Signal wires from the steering angle sensor and any other inputs (like vehicle speed from the ABS module) must be shielded to prevent electrical noise from interfering with the control module. If you are tapping into existing vehicle wiring, use proper connectors and solder joints, not wire nuts or crimp connectors that can loosen over time.

The control module itself must be mounted in a location that is dry, not too hot, and away from vibration. Many people mount it under the dash or in the engine bay. Once everything is wired, you reconnect the battery and test the system before driving the vehicle.

Programming and tuning the control module

After the wiring is complete, the control module must be programmed to work with your vehicle. If you are using a kit designed for your specific car, the module may come pre-programmed. If you are using a generic module or a module from a different vehicle, you will need to adjust settings like motor information curve, maximum information level, and steering angle offset.

The information curve determines how much power the motor provides at different steering wheel angles and vehicle speeds. At low speeds, you want more information so the wheel is straightforward to turn. At highway speeds, you want less information so the steering feels more responsive and stable. A poorly tuned curve will make the steering feel either too heavy or too light, or it may cause the wheel to jerk or oscillate.

Many aftermarket control modules can be tuned using a laptop or handheld programmer. If your module does not have this feature, you may need to adjust resistors or capacitors on the circuit board, which requires electronics knowledge. Some shops that specialize in steering conversions offer tuning services.

After programming, you should test the steering at low speed in a parking lot, then at highway speed on a quiet road. The steering should feel natural and responsive, with no dead zones, binding, or unexpected behavior.

Common challenges and how to avoid them

One of the most common problems is electrical noise causing the control module to malfunction. This happens when the motor draws current and creates electromagnetic interference that affects the sensor signals. To prevent this, use shielded wire for all signal lines, keep power and signal wires separated, and make sure all grounds are solid.

Another issue is steering feel. Electric power steering can feel numb or disconnected compared to hydraulic steering if the information curve is not tuned correctly. Some people find that the steering is too straightforward at highway speeds or too heavy at low speeds. This usually requires adjusting the control module settings or, in some cases, adding a mechanical feedback spring to the steering column.

Compatibility problems can arise if the control module does not communicate properly with your vehicle's other systems. For example, if your car has electronic stability control or lane-keeping information, the steering system must work with those features. This is why conversions on newer vehicles are often more complicated than conversions on older ones.

Finally, reliability is a concern. A hydraulic power steering system will still work even if the pump fails; you just lose information and the wheel becomes hard to turn. An electric system that loses power or has a control module failure may leave you with no steering information at all. For this reason, many people add a backup power supply or a manual override, though this adds complexity and cost.

When to hire a professional shop versus doing it yourself

If you have experience with automotive electrical work and steering systems, you may be able to do a conversion yourself. However, most people should hire a shop. Steering is a safety-critical system, and a mistake can make the vehicle undriveable or dangerous.

Look for a shop that has done electric power steering conversions before, ideally on the same make and model as your vehicle. Ask to see examples of their work and ask how they test the finished system. A good shop will have a way to measure steering response, test electrical connections, and verify that the system works correctly at different speeds and steering angles.

If you do the work yourself, plan to spend 40 to 100 hours depending on the complexity. You will need basic hand tools, a multimeter, a soldering iron, and access to the control module's programming software or documentation. You should also have a way to safely test the system before driving the vehicle on public roads.

Cost and timeline for a conversion

The cost of an electric power steering conversion varies widely. A complete kit for a popular vehicle (like a classic Mustang or Chevy truck) may cost $800 to $2,000. A custom conversion on an unusual vehicle or one that requires fabrication can cost $3,000 to $8,000 or more. Labor at a shop typically runs $50 to $150 per hour, and a full conversion may take 40 to 100 hours.

The timeline depends on whether you are using a kit or building a custom system. A kit conversion may take 2 to 4 weeks if the shop has the parts in stock and no complications arise. A custom conversion can take 2 to 3 months or longer if fabrication is needed or if the control module requires extensive tuning.

Before you commit, get a quote from the shop that includes parts, labor, and testing. Ask what warranty they offer on the work and whether they will support you if problems arise after the conversion is complete.

Frequently Asked Questions

Will electric power steering improve my fuel economy?

Possibly, but not dramatically. Electric steering uses less engine power than hydraulic steering because the motor only runs when you are actually turning the wheel. On a highway, the difference might be 1 to 3 percent better fuel economy. In city driving with frequent turns, the savings could be higher. However, the improvement depends on your driving habits and the efficiency of the electric motor and control module.

Can I convert a vehicle that already has power steering?

Yes. You are replacing the hydraulic system with an electric one, so the vehicle does not need to start with manual steering. In fact, converting a car that already has power steering is often easier because you can reuse some components like the steering column or angle sensor.

What happens if the electric motor fails while I am driving?

You will lose power steering information and the wheel will become hard to turn, similar to a hydraulic pump failure. You can still steer the vehicle, but it will require more physical effort. For this reason, some people add a backup power supply or a manual override. A well-designed system should also have a failsafe mode that alerts you if the motor or control module stops working.

Do I need to reprogram my vehicle's computer after the conversion?

It depends on your vehicle and the control module you use. If you are using a standalone module designed for your car, it may not need to talk to your vehicle's main computer. If you are integrating the steering system with other electronic features like stability control, you may need to reprogram or update your vehicle's main ECU. Ask the shop or kit manufacturer about this before you start.

Can I reverse an electric power steering conversion back to hydraulic?

Technically yes, but it is not practical. Once you remove the hydraulic pump and hoses, you would need to source and install a complete new hydraulic system, which is expensive and time-consuming. Most people who convert to electric steering keep it that way.