Check if WooCommerce cart has items, add link to have if it does

functions.php

<?php

function my_nav_wrap() {

  // checks if there is an item in the cart
  // returns default items + cart link if there is
  // returns default items if the cart is empty

  if (sizeof(WC()->cart->get_cart()) != 0) {
    $wrap  = '<ul id="%1$s" class="%2$s">';
    $wrap .= '%3$s';
    $wrap .= '<li class="cart">';
    $wrap .= '<a href="' . WC()->cart->get_cart_url() . '" class="cart_totals">';
    $wrap .= WC()->cart->get_cart_total();
    $wrap .= '</a>';
    $wrap .= '</li>';
    $wrap .= '</ul>';
  } else {
    $wrap = '<ul id="%1$s" class="%2$s">%3$s</ul>';
  }

  return $wrap;
}

line #13 should read:
$wrap .= '<a href="' . WC()->cart->get_cart_url() . '" class="cart_totals">';
you have an extra > before class="..