RigidBogy.AddForce does nothing.

I am trying to make a first person character controller, but my main movement AddForce call does nothing. I have already tried with very large numbers for the vector to move, with no effect. My code:

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;

 public class FirstPersonController : MonoBehaviour {

   public Camera cam;
   public float forwardSpeed = 8.0f;
   public float backwardSpeed = 4.0f;
   public float strafeSpeed = 4.0f;
   public float runMultiplier = 2.0f;
   public float jumpForce = 30f;
   public bool airControl = false;
   public float mouseSensitivity = 5.0f;
   public KeyCode RunKey = KeyCode.LeftShift;
   public KeyCode ESCKey = KeyCode.Escape;
   public KeyCode JumpKey = KeyCode.Space;

   private Rigidbody rb;
   private CapsuleCollider cc;
   private Quaternion originalRotation;
   private Quaternion camOriginalRotation;

   private float rx = 0.0f;
   private float ry = 0.0f;

   private bool paused = false;
   private float targetSpeed = 0.0f;
   private Vector3 targetMove;
   private bool isGrounded = false;
   private bool previouslyGrounded = false;
   private Vector3 groundNormal = Vector3.up;
   private bool jumping = false;
   private bool jump = false;

   void Start () {
     rb = GetComponent<Rigidbody> ();
     cc = GetComponent<CapsuleCollider> ();
     rb.freezeRotation = true;
     originalRotation = transform.localRotation;
     camOriginalRotation = cam.transform.localRotation;
   }

   void Update () {
     RotateCamera ();
     updatePaused ();
     getInput ();
   }

   void FixedUpdate () {
     Move ();
   }

   void RotateCamera () {
     if (!paused) {
       rx += Input.GetAxis ("Mouse X") * mouseSensitivity;
       ry = Mathf.Clamp(ry + Input.GetAxis ("Mouse Y") * mouseSensitivity, -90f, 90f);

       Quaternion xq = Quaternion.AngleAxis (rx, Vector3.up);
       Quaternion yq = Quaternion.AngleAxis (ry, Vector3.left);

       transform.localRotation = originalRotation * xq;
       cam.transform.localRotation = camOriginalRotation * yq;

       Cursor.lockState = CursorLockMode.Locked;
       Cursor.visible = false;
     }
     else {
       Cursor.lockState = CursorLockMode.None;
       Cursor.visible = true;
     }
   }

   void Move () {
     GroundCheck();
     if (rb.velocity.sqrMagnitude < (targetSpeed * targetSpeed) && targetSpeed > 0) {
       rb.AddForce (targetMove, ForceMode.Impulse); //This is the problem
       Debug.Log (targetMove);
     }
     if (isGrounded) {
       rb.drag = 0f;

       if (jump) {
         rb.drag = 0f;
         rb.velocity = new Vector3 (rb.velocity.x, 0f, rb.velocity.z);
         rb.AddForce (new Vector3 (0f, jumpForce, 0f), ForceMode.Impulse); //But this one works
         jumping = true;
       }

       if (!jumping && targetSpeed > 0 && rb.velocity.magnitude < 1f) {
         rb.Sleep ();
       }
     } else {
       rb.drag = 0f;
     }
     jump = false;
   }

   void getInput () {
     float h = Input.GetAxis ("Horizontal");
     float v = Input.GetAxis ("Vertical");

     targetSpeed = 0.0f;
     if (Mathf.Abs (h) > 0) {
       targetSpeed = strafeSpeed;
     }
     if (v < 0 && (Mathf.Abs (h) != 0 || backwardSpeed > strafeSpeed)) { //Always use the faster speed
       targetSpeed = backwardSpeed;
     }
     if (v > 0 && (Mathf.Abs (h) != 0 || forwardSpeed > strafeSpeed)) {
       targetSpeed = forwardSpeed;
     }

     if ((Mathf.Abs(h) > 0 || Mathf.Abs(v) > 0) && (airControl || isGrounded)) {
       targetMove = cam.transform.forward*v + cam.transform.right*h;
       targetMove = Vector3.ProjectOnPlane(targetMove, groundNormal).normalized;
       Debug.Log (targetMove);

       targetMove.x = targetMove.x*targetSpeed;
       targetMove.z = targetMove.z*targetSpeed;
       targetMove.y = targetMove.y*targetSpeed;
     }

     if (Input.GetKeyUp (JumpKey) && !jump) {
       jump = true;
     }
   } 

   void updatePaused () {
     if (!paused && Input.GetKeyDown (ESCKey)) {
       paused = true;
       Time.timeScale = 0.0f;
       Time.fixedDeltaTime = 0.0f;
     } else if (paused && Input.GetKeyDown (ESCKey)) {
       paused = false;
       Time.timeScale = 1.0f;
       Time.fixedDeltaTime = 0.02f;
     }
   }

   void GroundCheck()
   {
     previouslyGrounded = isGrounded;
     RaycastHit hitInfo;
     if (Physics.SphereCast(transform.position, cc.radius, Vector3.down, out hitInfo,
       ((cc.height/2f) - cc.radius) + 0.01f, Physics.AllLayers, QueryTriggerInteraction.Ignore))
     {
       isGrounded = true;
       groundNormal = hitInfo.normal;
     }
     else
     {
       isGrounded = false;
       groundNormal = Vector3.up;
     }
     if (!previouslyGrounded && isGrounded && jumping)
     {
       jumping = false;
     }
   }
 }

I have another AddForce for jumping, which works, so I have no idea what is causing the problem. Any help is appreciated.