Finally (after 3 weeks of fiddling with this) I along with help from Crowbar Bob have figured out the problem and settled the circuit's issues. Bob discovered another gentleman had posted this same circuit on the Stovebolt site some time ago. And I discovered it also posted by a man in Canada who was trying to add intermittent wipers to his Volvo. The Canadian fellow said the circuit sort of worked for him but had problems. I'm pretty sure I know what he meant. This was a very popular circuit shared far and wide in the 1970s and I've used it or variants of it for a few different things since I first saw it...but for intermittent wipers using one of the popular "drop-in" electric wiper conversion kits it simply will not work. Not without a couple of changes anyhow. The good news is I now have 4 intermittent speeds, regular low and regular high. The better news is I can use one single inexpensive imported Bosch-style relay and mount it on the firewall or somewhere outside the cab where it won't be clicking when the wipers are in intermittent mode. When I have time to draw a new circuit schematic, I'll post it.
