My 2001 Grand Caravan ES has an issue with the turn signals. When you engage the right turn signal it immediately switches to the left signal. Left works just fine, it only does this when using the right signal.

 

I'd bet on a bad switch especially if it is physically switching to the left. Other than that you're looking at a Body Control Module (BCM), Front Control Module (FCM), or Integrated Power Module (IPM). Test the switch using the ohm's function on a multimeter. Check connections for any damage/corrosion at the FCM/IPM connection and at the bottom of the IPM - a known problem area. Disconnect the negative battery cable first.