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Hey guys I am getting ready to fire up my engine on my test stand, and I am trying to get my head around the actual starter/ignition wiring. I am using a PSI Conversions wiring harness, and I have everything plugged in and ready to go. I plan to use a 4 position key switch to turn the motor on and off on the test stand. My question is regarding where everything lands on the terminals of the key switch. There is a red wire that comes from the fuse block and needs to have 12v going to it. My sketch below shows the red wire from the fuse block going to the "Starter Solenoid" terminal, but I am second guessing myself, and I feel like it should go to the accessory or ignition coil terminal. Any help you guys could provide would be greatly appreciated.
The red wire in the under-dash harness needs +12v when key is on and cranking. Hook that up to the ignition output of your key switch and you'll get what you need. Hooking it up to the starter position, the engine would fire when you hit the starter, but as soon as you let off the key it would die. Also, make sure you hook up the large battery positive wires to the main +12v pole on your starter that you have the wiring coming from the battery drawn to, not on your solenoid.
Thank you that’s what I was thinking. So in my diagram I would terminate the red wire from the fuse block to the ignition coil terminal on my switch, correct?
Correct, connect that wire to the ignition terminal on your switch. Also, make sure you connect the battery positive wires at the starter to the pole with your large main battery cable.
Yeah, move those 2 to the terminal on your starter where the battery positive cable is. Move the one you have drawn from the fuse block to the ignition terminal on your key switch and you're set.
You bet! Most people run into no-start issues because they hook that wire up to an "accessory" source. Accessory gets 12v when the key is on, but not when it's cranking. To fire, the system needs power to that wire for both on and crank, the ignition terminal will give you that. PSI makes a nice harness, mine did come with 2 wires on the drive-by-wire connector switched around, but it was easy to pop the pins out and switch them once I traced the issue down.
My ignition switch came on today, and I am trying to get some time in the garage this weekend. I will post a final schematic, and pictures when I have it all wired up.
Does anyone know which wire and color is the serial data wire on thos harness? Normal harness is dark blue pin 18 x1 plug. I need to know what it is on the psi harness
my harness is a GEN IV LSX/Vortec. With 6l80E
12-12-2017, 06:42 PM
PSI Wiring Harness Question 
