2002 Dodge Caravan

Remove the switch and disconnect the wiring. Use an ohmmeter, it will show continuity or no continuity as you use the meter probes and move the switch in different positions. If you disconnect the rear wiper trim cover you can use a voltmeter to see if a signal is being sent when you switch it on also, but this is the hardest and worst way to test it, because a body computer is used. It works but is more work. Test all the fuses and relays also, they are in a power center under the hood, near the battery.