Need help fixing error (NullReferenceException: Object reference not set to an instance of an object)

So here's my code:

 using UnityEngine;
 using System.Collections;
 using UnityStandardAssets.Vehicles.Car;
 using UnityStandardAssets.Characters.FirstPerson;
 
 public class ControllerManager : MonoBehaviour {
     private CarUserController CarController;
     private RigidbodyFirstPersonController Player;
     private CarAudio CarSound;
     public Camera PlayerCamera;
     public Camera CarCamera;
     // Use this for initialization
     void Start ()
     {
         CarController.enabled = false;
         Player.enabled = true;
         CarSound.enabled = false;
         CarCamera.enabled = false;
         PlayerCamera.enabled = true;
 
     }
 
     // Update is called once per frame
     void Update()
     {
 
         if (Input.GetKeyDown(KeyCode.E))
         {
             SwitchCamera();
         }
     }
 
     void SwitchCamera()
     {
         CarController.enabled = !CarController.enabled;
         CarCamera.enabled = !CarCamera.enabled;
         CarSound.enabled = !CarSound;
         Player.enabled = !Player.enabled;
         PlayerCamera.enabled = !PlayerCamera.enabled;
     }
 }
 

I get the error on line 15: CarController.enabled = false; I made this script for switching the player and car controllers. It's weird because the car controller is getting the error, but the player controller isn't (Player is the player controller btw). Anyway, anyone know where I went wrong?

EDIT: I just realized that the same thing is happening with all of Unity's car scrips.... almost same exact thing. Here's the one for cross-platforming controlls:

 using System;
 using UnityEngine;
 using UnityStandardAssets.CrossPlatformInput;
 
 namespace UnityStandardAssets.Vehicles.Car
 {
     [RequireComponent(typeof (CarUserController))]
     public class CarUserControl : MonoBehaviour
     {
         private CarUserController m_Car; // the car controller we want to use
 
 
         private void Awake()
         {
             // get the car controller
             m_Car = GetComponent<CarUserController>();
         }
 
 
         private void FixedUpdate()
         {
             // pass the input to the car!
             float h = CrossPlatformInputManager.GetAxis("Horizontal");
             float v = CrossPlatformInputManager.GetAxis("Vertical");
 #if !MOBILE_INPUT
             float handbrake = CrossPlatformInputManager.GetAxis("Jump");
             m_Car.Move(h, v, v, handbrake);
 #else
             m_Car.Move(h, v, v, 0f);
 #endif
         }
     }
 }
 

The error is on line 27: m_Car.Move(h, v, v, handbrake);