In the case of rectilinear vehicle movement, the hydraulic control unit circulates the fluid (from the pump through the channels to the tanks).
When the steering wheel is turned, the torsion bar is twisted, which is accompanied by rotation of the spool relatively to the distribution sleeve. On the opened channels, the liquid enters one of the cavities (depending on the direction of rotation) of the power cylinder. From the other cavity of the power cylinder, liquid flows into tanks through the opened channels. The piston of the power cylinder ensures the movement of the steering rack. The force from the rack is transferred to the steering rods and further leads to the rotation of the wheels.
When making a turn at a low speed (when parking, maneuvers in a limited space), the power steering works with the greatest performance. Based on the sensor signals, the electronic control unit increases the speed of the pump motor (providing the opening of the solenoid valve). Accordingly, the pump capacity increases. A special liquid enters the power cylinder more intensively. The force on the steering wheel is greatly reduced.
As the speed of movement increases, the speed of the pump motor decreases (the solenoid valve is activated and the cross-section of the hydraulic system decreases).
The operation of the hydraulic amplifier is carried out within the limits of the steering wheel rotation and is limited by a safety valve.
Where are the fuses? In the interior, the mounting block is located at the left end of the dashboard. To access it, you need to open the driver’s door and remove the lid.
Also, the fuses can be on the block under the hood. The sub-hood assembly unit is located on the left side, between the battery and the coolant expansion tank. Some details are more difficult to access, for example, a relay in the torpedo at the driver’s feet.
These relays are located under the dashboard on a special bracket, close to the pedals, so you need to lie down to get close to them.
Nevertheless, it is quite easy to understand this system and often car owners do not even need to seek help from car repair shops to cope with a breakdown or a problem.