Wierdbeard65 on "add_filter('wp_nav_menu_items' not working?"

Hi,

I'm trying to add a login option to the main menu bar of my theme. Virtually all the solutions I have found with google amount to the same method, which is to add a function to create the entry and call that function by adding something like:
add_filter('wp_nav_menu_items', 'add_login_logout_link', 10, 2);
to my functions.php (where add_login_logout_link is the name of my function.
My problem is that the link never shows up. I did a var-dump of the wp_filters and it is getting added, so...?

Anyone else had this problem / got it working?

Thanks!