How to rotate a object

I want to rotate my car when I either press A or D, but it doesn't work with my code, what is the problem with my code?

 var RiderSpawn : Transform;
 
 var FinalRiderSpawn : Transform;
 
 var Player : Transform;
 
 var IsRiding : boolean = false;
 
 var MovementScript : CharacterMotor;
 
 var DrivingSpeed : float;
 
 var DefaultPlayerRotation : Quaternion;
 
 var GotOut : boolean = false;
 
 var TruckCollider : Collider;
 
 var TruckCollider2 : Collider;
 
 var Truck : GameObject;
 
 var IsDriving = false;
 
 function Start () {
 
 }
 
 function Update () {
 
 if(IsRiding == true){
 Player.position = RiderSpawn.position;
 Player.rotation = RiderSpawn.rotation;
 }
 
 else
 
 if(IsRiding == false && GotOut == true){
 Player.rotation = (DefaultPlayerRotation);
 GotOut = false;
 }
 
 
 
 if(Input.GetKey(KeyCode.W) && IsRiding == true){
 
 Truck.transform.Translate(Vector3.right * DrivingSpeed * Time.deltaTime); //The reason why I use ".right" instead of forward is because it goes to the left when I use ".forward" . So if you know how to fix this as well, it would mean a lot to me
 IsDriving = true;
 }
 
 if(!Input.GetKey(KeyCode.W)){
 
 IsDriving = false;
 
 }
 
 if(Input.GetKey(KeyCode.A)){
 
 Truck.transform.Rotate(Vector3.left * DrivingSpeed * Time.deltaTime);
 
 }
 
 if(Input.GetKey(KeyCode.D)){ 
 
 Truck.transform.Rotate(Vector3.back * DrivingSpeed * Time.deltaTime);
 
 }
 
 
 
 
 }