the_excerpt() wont work?

Hi ,
I have a problem with <?php the_excerpt();?>
when I click on the […] nothing happends? Arnt it suppose to show the whole text?

I also tried to put

function new_excerpt_more( $more ) {
	return ' <a class="read-more" href="'. get_permalink( get_the_ID() ) . '">Read More</a>';
}
add_filter( 'excerpt_more', 'new_excerpt_more' );

in the functions file but when I click read more, nothing happend…what could be wrong ? I use a custom post type…