What is the function of each wire in a three-wire ignition coil?

[LeAnthony]

The functions of each wire in a three-wire ignition coil are as follows: 1. 1-wire ignition coil: Primary coil positive; Primary coil negative (signal). There are two wires on one ignition coil, one for power supply and one for signal. One ignition coil controls the ignition of two cylinders. This type is commonly found in minivans. It can be tested using an LED test light or the HZ range of a dedicated automotive multimeter. 2. 2-wire ignition coil: Primary coil; Primary coil negative (signal); Secondary coil negative. To make the starter operate, you can test its signal with an LED test light, which will flash. You can also measure its frequency using the HZ range of a dedicated automotive multimeter to determine whether the computer is providing a signal to the ignition coil. 3. 3-wire ignition coil: Primary coil power supply; Ignition signal wire; Primary coil ground; Secondary coil ground. The signal waveform is also a square wave, but the signal voltage is smaller and may not be able to drive an LED indicator. It is recommended to use the HZ range of a dedicated automotive multimeter or an oscilloscope to detect its signal.