The first schematic I've drawn is attached Kevin. There are a couple of resistor values I'm still playing with, I'm considering using slightly different transistors (these are 2 very common general application types which might or might not be responsive enough) and I don't have the 8 position rotary switch yet but here's how it works:
12v + comes in from the wiper switch (via the low speed lug). Ground provides the 12v - for the control. If the rotary switch is set to the 1st position, the 12 volts runs straight through to the low speed circuit of the wiper motor and runs as normal. If the switch is set to the 2nd position, the 12 volts runs through to the high speed circuit of the motor and runs as normal. If the switch is set to the third position, then some resistance/capacitance magic occurs, a couple of transistors get to flip and flop and do their thing and then the 12 volts runs through the normally open contacts of the relay to the low speed circuit of the motor as a pulse when the contacts of the relay close. Running through the 33k resistor, the pulse rate is once every 2 seconds. Running through the 75k resistor, the rate is once every 3.8 seconds. Running through the 120k resistor, the rate is once every 6 seconds and running through the 180k resistor, the rate is once every 8.5 seconds. When the wiper motor senses there's no current, it goes to park and waits. Part of my curiosity at this point is "does the 2 second sweep give the motor enough time to park and wait, or is that too fast for this motor?" Once I finish building it, we'll see. There's in my mind the possibility I might have to make 3.8 seconds my fastest speed and add an option for 10 seconds or so.
~ Jon 1952 1/2 ton with 1959 235 | T5 with 3.07 rear end
