Has anyone made/added an intermittent circuit to their rear wiper so it's only going once or twice a minute instead of always on?

 

I couldn't figure out how to add this into the sub's system without adding another switch. Has anyone done this and were able to do it without adding another switch?

I have been contimplating rigging the switch from the column of another car into the dash and have int, low, and high for the rear wiper. However just have it be int or off would work for me. I heard you can use the relay from the front wipers to make the rear int.