67 Dart windshield wipers not working

They made both 2 speed and variable speed wipers that year. I recommend you get a wiring diagram for your year/model and run a test hot wire to the wiper motor to make sure it works before you start digging into the dash. If it works, then start testing the switch. If the motor doesn't work, first check to make sure the ground strap is good, tight, and not corroded.