Circuit Operation

With the ignition switch in ON (II) or START (III), voltage is applied to the ignition coil and the ignition control module (ICM). As the distributor shaft turns, the ignition control module (ICM) acts as a switch to control current flow through the primary winding of the ignition coil. When the current flow stops, a high-voltage current is induced in the secondary winding of the ignition coil. This high-voltage current flows through the distributor cap and rotor to the proper spark plug.