I get it now!!
Ignition 2 is the start mode and has 12 volts while cranking (brown wire).
Ignition 1 is run mode (blue wire). It has 12 volts when you let off the key when the engine starts.
The diode is basically a check valve. It only allows current to flow 1 way.
The diode gets wired from ignition 2 to ignition 1. This will allow 12 volts from the ignition 2 start (or crank) mode to flow to ignition 1 run mode. When the engine starts and you let off the key the diode (or check valve) prevents the 12 volts from ignition 1 from flowing back to ignition 2. Thus, ignition 1 always has 12 volts and the Fitech is happy.
Correct... the Diode keeps working the ballast to the coil in run correctly with the decayed power.
there was a nice discussion about this couple of months ago. A relay can be used too allong with diode, but makes a bigger and "complex" installation. Not required if the source needed is mainly just for triggering, and not for sourcing more than the stock system
