I can't help you with the aftermarket stuff and maybe someone will chime in with that.On the Astro/Safari vans there is a relay and a circuit board right inside the wiper motor.When you think of the size of one of those van's windshields,there is a fairly wide swing.If you haven chosen a steering column yet,the ones from these vans have a good size with the standard clamp main brace under the dash and a four bolt flange to the firewall to a universals to a intermediate shaft.There are tilt versions which are not that hard to find,but have a shifter on the column for the automatics.There is a ton of those vans out there.The stick shift versions of those vans where only available 1985 to 1989 and some where tilt with the proper controls for the wipers that you want.Those are somewhat more rare,but are out there as well.