Yes, they do.
http://www.pelicanparts.com/catalog/shopcart/9144/POR_9144_electr_pg5.htm#item25
Next time it fails, try tapping on the starter. Sometimes they stick. If that doesn't work, try pushing the car backwards a foot or two while in gear. That can sometimes move things to a fresh position where they work.
There are quite a few other checks in the article, go through them when you get a chance.
--DD