Circuit Operation

With the ignition switch in RUN or START, voltage is applied to the ignition coil. 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 current flow through the primary winding is stopped, 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.