How can I rotate a steering wheel to its original rotation in Unity3D?

Question

I have been searching for an answer for hours, and I cant find the solution. I have a script that rotates a steering wheel when the car is turning. It has maximum rotation of 120 and a minimum rotation of -120. I have been trying to rotate with RotateTowards and other Quaternion methods but I can't figure them out. How can I make it when the turning angle is not zero and turning keys (a and d) are not pressed, it goes to its original rotation of 0, 0, 0, at a certain speed?

Here's my script for the steering wheel:

    if (horizontalInput > 0)
    {
        wheel.transform.Rotate(Vector3.forward*Time.deltaTime*wheelspeed);
        rotations -= wheelspeed;
    }
    else if (horizontalInput < 0)
    {
        wheel.transform.Rotate(-Vector3.forward * Time.deltaTime * wheelspeed);
        rotations += wheelspeed;

    }

And here is my (very bad) script for the minimum and maximum rotation of the steering wheel:

    angle += Input.GetAxis("Horizontal") * Time.deltaTime*10;
    angle = Mathf.Clamp(-120, angle, 120);
    wheel.transform.localRotation = Quaternion.AngleAxis(angle, Vector3.forward);
    
   
    angle += Input.GetAxis("Horizontal") * Time.deltaTime * 400;
    angle = Mathf.Clamp(120, 0, angle);
    wheel.transform.localRotation = Quaternion.AngleAxis(angle, Vector3.forward);

Answer 1

I would do what @ken is doing, but refactor the speed factors and other constants into fields so they are more easily changed and also use Mathf.MoveTowardsAngle to move the angle back to its neutral position.

[SerializeField] float rotateBackSpeed = 3f; // degrees per second
[SerializeField] float rotateSpeed = 10f;    // degrees per second
[SerializeField] float angle = 0f;           // degrees
[SerializeField] float minAngle = -120f;     // degrees
[SerializeField] float maxAngle = 120f;      // degrees
[SerializeField] float neutralAngle = 0f;    // degrees

void Update()
{
    angle = Mathf.Clamp(angle + Input.GetAxis(“Horizontal”) * rotateSpeed 
            * Time.deltaTime, minAngle, maxAngle);

    if (Mathf.Approximately(0f, Input.GetAxis(“Horizontal”))) 
    {
        angle = Mathf.MoveTowardsAngle(angle, neutralAngle, 
                rotateBackSpeed * Time.deltaTime);
    }

    transform.eulerAngles = angle * Vector3.forward;
}