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LS wiring question


New Member
Jul 6, 2022
Installing a crate ls3 getting ignition wiring figured out (forgive me this is the first time Ive installed any engine)
have two wires one labeled constant for ECM
the other says switched 12V.

Dont see a ground wire on the harness.

I was wanting to run a battery cut off switch


Do I wire the constant as a constant... dont run off the battery disconnect bus bar? Or can I shut the ECM down every time I shut off the buggy?

Is the switched 12v how I would shut the engine off?

Is the ECM grounded through the case to chassis connection?


Well-Known Member
Jan 27, 2013
Constant goes direct to battery, do not put a kill switch on it.

Switched power goes through a switch. This switch is how you turn the ECM on and off, and the engine with it.

You can also add a battery switch if you want before the aforementioned switch.

ECM case doesn't need to be grounded. There are ground pins that will provide the ground for the electronic components inside. There are multiple grounds to install on the engine, one of them handles that aspect.

Also, read the manual that comes with the harness.
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