Ignition Coil Testing involves looking for coil negative control. This test can be performed (using an incandescent test light) on any coil where the driver is not part of the coil assembly. (conventional, most waste spark systens and 2wire C.O.P.)

On the 3 and 4 wire C.O.P.s, coil negative cannot be accessed directly as it is internal to the coil, however the coils trigger signal can be viewed similarly using an LED type of test light.

DO NOT use an LED test light to monitor coil for pulsing/control (shown in this video) because the 300400v spikes that occur during the collapse of the magnetic field will cook the LED