Conversion to intermittent wipers

If I remember correctly, it goes in line on the park wire from the wiper switch. it gives a signal of a second or two for park and you adjust the time between it sends the signal. And when off, the circuit is normally closed. Again, installed it a while ago, so I just installed it in line from the switch to the wiper, first wire did not work, second one did. plus it has it's own ground and acc power. Also used a left over window crank knob so looks like a factory option