Brand new coil 89 Dodge ram 250 3.9 van, test light lights on positive doesn't light on negative, no spark through coil wire

With engine cranking, if you have voltage to ignition coil, the problem isn't the asd relay. The ignition module, if you want to word it that way, is in the computer. The computer switches the negative side of coil, ground on and off, to induce secondary ignition voltage. With engine cranking, test light at coil terminal, does it pulse? If not, there is a problem on that circuit somewhere. Just my opinion.