I recall a moment when my windshield wipers didn't work, but after I shut down and restarted they worked fine. Well, now they don't work at all. How should I go about a diagnosis to find the culprit. Is it highly likely that it is the motors, and I should just replace them? I can still use the wiper fluid, so I think the switch is still working properly. My Jeep has around 120,000 miles and is a '99 TJ. Is this a common problem with aging Jeeps?