Quick question about my alternator wiring. I am running a GM 3 wire alternator with an EZ wire harness. I plan on connecting the white alternator exciter wire to T2. (not just jumpered to the alternator like in the picture). My question is do I need to install the diode coming from T1 to the load side of the ignition switch like in the picture if I am using a HEI? I read it helps to eliminate engine run on.... Thanks in advance.
Exciter wire needs to go to T1, diode will not be needed if exciter wire is powered from accessory terminal of ignition switch.
I always run the diode, it prevents feedback. That's why its used to stop run-on. There are any number of reason for feedback once you start adding accessories unless your switch has a dedicated terminal for it and nothing else, which is rare.
The diode prevents feed back if you have the exciter wire hooked to the ignition side of the ignition switch rather than the Accessory side. The majority of us have either put together a car with an alternator or worked on one that wouldn't shut off when you turned the key off because it was feeding the ignition from the alternator. Hooking up the T2 wire the way you plan is fine. I've had them hooked both ways.
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