The 12 volt electrical system of the Aermacchi SS and SX 350 with starter motor, drawn circuit by circuit. Each wire is labelled with its colour.
Always check a wire with a multimeter before you connect it, and disconnect the battery first.
Circuit 1Power from the batteryThe positive goes through the fuse to the ignition switch. The negative runs to the starter motor and earth.
Circuit 2ChargingThe alternator supplies AC. The regulator turns it into DC and charges the battery.
Circuit 3StartingThe start button energises the relay. The relay sends the heavy current to the starter motor.
Circuit 4IgnitionThe coil gets power through the ignition switch. The points switch the coil, and the coil gives the spark to the plug.
Circuit 5Headlamp and parking lightThe changeover switch sends the current to the headlamp or to the parking light.
Circuit 6Tail light and clocksThe same yellow wire feeds the tail light and the instrument lighting.
Circuit 7Stop lightBoth brake switches get power after the ignition switch. Either one is enough to light the stop light.
Circuit 8HornThe horn has positive after the ignition switch. The button on the handlebar makes the earth.
Circuit 9Turn signalsThe relay passes the current in pulses. The switch selects side A or B.
Read this firstWatch out forUncertain colours and terminals
- 2-colour means a two-colour wire whose colours are not certain. Other wire colours may also differ, especially red, black and white.
- Terminal numbers are on the parts themselves. Check with a meter which ignition switch terminals are connected in each key position.
- KA and KB are the two turn signal sides on the handlebar switch. Check which one is left or right.
- The turn signals are earthed through the frame.
- There are connectors in the wires to the rear.
- The rev counter lamp is fitted to the SS only.
Our own drawings per circuit. The connections are based on the workshop manual for this model. Not an official publication of the manufacturer.