with the ballast unhooked if you put 12V to one end you will get 12 on the other end. the reduction does not start until it is hooked up/current starts flowing in operation. With it unhooked just ohm each end & post the number you get/what resistor you are working with/what coil etc & I'll see if I have some numbers (ohms) that apply to it & if we can improve it for your app (if a 4 terminal ballast).