I bought a brand new AC/Delco dual action pump around 1970 thinking the same thing. As it turned out, it was a great incentive to convert to electric wipers and would have been a decent trot line weight if you had a trot line with only 3 or 4 hooks. Aside from that it was a waste of $ and as others have already said, it was not a solution to driving uphill at all. A couple of years ago I wrote a circuit for adding delay wipers to the AD that used the same switch knob. You end up with low speed, high speed and 4 different speeds of delay wipers. It is still around here somewhere and not difficult to do now that all the work has been done.
