Custom search results by taxomony

Ok so here goes, i have created a custom search, i want my users to be able to search for businesses (custom post type) and filter them by two taxonomies(location and category). I have this working, so far by using the following searchform

<form role="search" method="get" id="searchform"
    class="searchform" action="<?php echo esc_url( home_url( '/a3/' ) ); ?>">
    <div>
        <fieldset>
        <label class="screen-reader-text" for="s"><?php _x( 'Search for:', 'label' ); ?></label>
        <input type="text" value="<?php echo get_search_query(); ?>" name="s" id="s" />
        <?php #echo buildSelect('business-category') ?>
        <select class="select2" name="business-category">
          <?php
            // generate list of categories
            $taxonomies = get_terms('business-category');
            foreach ($taxonomies as $tax) {
            	echo '<option value="', $tax->slug, '">', $tax->name, "</option>\n";
            }
          ?>
        </select>
        <select name="location">
          <?php
            // generate list of categories
            $taxonomies = get_terms('loc');
            foreach ($taxonomies as $tax) {
              echo '<option value="', $tax->slug, '">', $tax->name, "</option>\n";
            }
          ?>
        </select>

        <input type="submit" id="searchsubmit"
            value="<?php echo esc_attr_x( 'Search', 'submit button' ); ?>" />
        </fieldset>
    </div>
</form>

and adding this to my functions

function advanced_search_query($query) {

	if($query->is_search()) {

		// tag search
		if (isset($_GET['taglist']) && is_array($_GET['taglist'])) {
			$query->set('tag_slug__and', $_GET['taglist']);
		}

		return $query;
	}

}
add_action('pre_get_posts', 'advanced_search_query', 1000);

what i am trying to achieve is to have the option when the user selects a category or location or both but does not enter a search term to list said category, location or join of the two.