If the vehicle is equipped with a manual transmission and is not equipped with a starter thermal switch (HD starter with overcrank protection), voltage is applied to the ether injection/ engine coolant temperature (ECT) switch when the ignition switch is in the START position, and the clutch starter/ interlock switch is closed (clutch pedal fully depressed). The ether injection/ engine coolant temperature (ECT) switch closes when the ambient temperature is below -5°C (23°F). Voltage is then applied to the ether injection control valve. Since the ether injection control valve is permanently grounded at G101, the valve energizes, and ether is injected into the intake manifold.

If the vehicle is equipped with a starter thermal switch (HD starter with overcrank protection), engine cranking may be interrupted if the starter motor becomes too hot from an extended cranking period.

If the vehicle is equipped with an automatic transmission and is not equipped with a starter thermal switch (HD starter with overcrank protection), voltage is applied to the neutral position switch when the ignition switch is placed in START. The neutral position switch closes when the transmission shifter is in the neutral position. With the ignition switch in START and the neutral position switch in neutral, voltage is available to the ether injection/ engine coolant temperature (ECT) switch. The ether injection/ engine coolant temperature (ECT) switch closes when the ambient temperature is below -5°C (23°F). Voltage is then applied to the ether injection control valve. Since the ether injection control valve is permanently grounded at G101, the valve energizes, and ether is injected into the intake manifold.

If the vehicle is equipped with a starter thermal switch (HD starter with overcrank protection), engine cranking may be interrupted if the starter motor becomes too hot from an extended cranking period.

If the vehicle is equipped with a starter thermal switch (HD starter with overcrank protection), engine cranking may be interrupted if the starter motor becomes too hot from an extended cranking period.