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bigblktrk · 08-28-2011, 09:11 PM

The ECM1 slot is a 10 amp fuse and from what I see there is a junction in the harness of 6 wires. GM likes to crimp and solder these then wrap them in fabric tape. An easy way to find it I believe the red wire from injector 1 and the white wire from injector 2 tie into it. If I remember, it is on the passenger side between the head and intake. The other 4 go to the ESC (Electronic Spark Control.. won't apply to you 7.4 does not have this), the ECM (bundle of wires goes through the firewall on passenger side by rear of engine, AIR diverter valve (located by AIR pump), and the EVRV (EGR control) Valve (The vacuum line comes off it to the EGR valve).
The wire is a pink/black wire and is ignition on.
Don't be confused with other pink/black wires other than the above ones.
There is a pink/black wire that comes off of the ignition fuse and feeds a lot of the coils on the relays.
Hope this helps.

08-28-2011, 09:11 PM	#8
bigblktrk Registered User Join Date: Feb 2011 Location: S. Windsor, CT Posts: 16	Re: Bad ECM? The ECM1 slot is a 10 amp fuse and from what I see there is a junction in the harness of 6 wires. GM likes to crimp and solder these then wrap them in fabric tape. An easy way to find it I believe the red wire from injector 1 and the white wire from injector 2 tie into it. If I remember, it is on the passenger side between the head and intake. The other 4 go to the ESC (Electronic Spark Control.. won't apply to you 7.4 does not have this), the ECM (bundle of wires goes through the firewall on passenger side by rear of engine, AIR diverter valve (located by AIR pump), and the EVRV (EGR control) Valve (The vacuum line comes off it to the EGR valve). The wire is a pink/black wire and is ignition on. Don't be confused with other pink/black wires other than the above ones. There is a pink/black wire that comes off of the ignition fuse and feeds a lot of the coils on the relays. Hope this helps.