Circuit/System Description

The engine controls ignition relay is a normally open relay. The relay armature is held in the open position by spring tension. Battery positive voltage is supplied directly to the relay coil and the switch contact at all times. The engine control module (ECM) supplies the ground path to the relay coil control circuit via an internal integrated circuit called an output driver. When the ECM commands the engine controls ignition relay ON, ignition voltage is supplied to the ECM and to several additional circuits.