I just picked up a 88XJ and the wipers all act funny in the front. When I twist the wiper arm back it does the 1 wipe. It shows on the handle, intermittent wipers and slides into like 3 positions, but only the full speed last setting works. Also it seems that when the windshield isn't wet they can hardly move. How do I test to see if the motor needs to be replaced of if it's something else? And what's the deal with the handle and the intermittent wipers? Any ideas? Please help. Thanks!