Most likely you problem is the wiper motor.
The wiper motor has an internal switch that controls the intermittent function as well as parks them in when the reach the down position rather than just shutting them off when ever you turn the switch off.
Just recently at work I replace the wiper motor on a 2003 Camry with the same concern
I cant remeber for sure but i think there may be two different wipermotor/wiper-transmission combinations on the Tacoma. Either Denso or Valeo so look to see what kind you have before you look for a replacement.
