Sometimes when i turn off my pop headlights one stays up how come is that?

pop up

My first 89 240sx I bought did this on occasion. Its got to be because of the the Relay to it or the Motors are going bad that move the headlights up and down. I'm not too sure how to fix this <img src="#/f/iB_html/non-cgi/emoticons/sad.gif" border="0" valign="absmiddle" alt=':('>