1. Battery voltage: This wire connects the positive terminal of the battery to the primary winding of the ignition coil.
2. Ground: This wire connects the negative terminal of the battery to the secondary winding of the ignition coil.
3. Distributor: This wire connects the ignition coil to the distributor, which then distributes the high voltage current to the spark plugs.
Some vehicles may have additional wires connected to the ignition coil for features such as a tachometer or engine management system.