I think there’s three things going on with your code.
The first is that you’re passing a numeric string as the first parameter to has_term(). If you’re trying to pass the term ID to the function, you should remove the quotes from ’16’ and just pass 16, i.e. as integer.
https://developer.wordpress.org/reference/functions/has_term/
The second is that you’re using has_term() to load on a certain taxonomy page. That function is for checking if a post has certain term, not if the query is for a taxonomy page. You should use is_tax( $taxonomy, $term) instead.
https://developer.wordpress.org/reference/functions/is_tax/
The third thing is that you’re doing the conditional check directly on the functions.php file. Due to loading and actions firing order, the check happens too early. Wrap the check in a callback function and attach that for example to template_redirect action hook. By the time that action happens WP has set up itself proprely and the conditional function has the necessary data to check against.
https://codex.wordpress.org/Plugin_API/Action_Reference