Typically, when an ignition control module of this type fails it would be one of the three drivers (transistors) within it that controls a specific ignition coil giving up.

Follow along as we install this new MSD Digital-6 ignition control module on our off road truck! See all the details and every thing that comes with this MSD unit in this months issue of Off-Road ...

The Ignitor is about the simplest ignition upgrade you can make, since its just a little module that drops in to replace ignition points in a stock distributor.