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5.3 v8 swap, need some help with cranking system

512 Views 17 Replies 6 Participants Last post by  Thawk
I am to the point with my swap where i need to figure out the wiring to crank the new motor with the key switch. i'm just having a hard time finding the signal wire coming from the key switch. i have the yellow wire for the starter relay under the hood, just need the under dash wiring. Anyone familiar?
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Hopefully , someone will have the GM diagram but for now see attached.
The request from BCM goes to Engine ECM and it grounds the start relay.
does not appear to be an ignition switch type you can just " run a wire from "


What truck ECM exactly and calibration?
Numbers on ECM ?
411 it appears
I was trying to see if ANY applications - calibrations using your PCM could but no.
2005 E40 24x is earliest I see of this but no one in their right mind would convert to an E40.

Easy to say from the sidelines , a 58 reluctor, E38 and treat the whole deal as a GT would be my route.

I have no idea if the resistor in the switch for the start circuit is accessible.
If it was , possibly bridging it would allow you to run a relay control across circuit 1073 and 1390.
I'm bench racing at this point.
Good luck.
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