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Old 08-14-2017, 03:58 PM   #1
WB72
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LS wiring Harness layout

I have a 2002 5.3l LM7 truck engine that I am going to install in my 67.

I purchased a bunch of parts, so I don't have the donor truck to reference the layout of the wiring harness. Surprisingly, there isn't a lot of information about this online.

Is there a rough diagram on where the harness lays on the engine?

Where is the PCM located on this?

What position does the harness enter the engine?

Does it wrap around the front, how does it go to the bottom of the oil pan?

If anyone has pics of this in their build thread, let me know where I can look.
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Old 08-14-2017, 05:03 PM   #2
rctrooper1
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Re: LS wiring Harness layout

the original harness will come out from the driver side over the valve cover and the pcm is located on the driver side wheel well. once you modify the harness you may opt to change where you want the pcm located.
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Old 08-14-2017, 07:33 PM   #3
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Re: LS wiring Harness layout

I will start with that, Thanks. to get to the Passenger side, does the rest of the harness go around in the front or rear of the engine?

For starters, I would like to get it laying in its stock configuration.
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Old 08-15-2017, 12:09 PM   #4
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Talking Re: LS wiring Harness layout

Check out this website;
http://lt1swap.com
He has most up to date info on the specific LS/Vortec pin outs and pcms to use,etc... lots of good info on how to do your own "wire diet" there are many YouTube videos that explain how to do this with four wire hook up, but you will still need to re program the pcm to remove VATs (anti theft system) other than that, he also does pcm programming too!
Hth,
Ben
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Old 08-15-2017, 01:53 PM   #5
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Re: LS wiring Harness layout

Quote:
Originally Posted by snipescastle2 View Post
Check out this website;
http://lt1swap.com
He has most up to date info on the specific LS/Vortec pin outs and pcms to use,etc... lots of good info on how to do your own "wire diet" there are many YouTube videos that explain how to do this with four wire hook up, but you will still need to re program the pcm to remove VATs (anti theft system) other than that, he also does pcm programming too!
Hth,
Ben
Yes, Brandon has a great site. I am looking for the basic where the loom sits on the engine.
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Old 08-15-2017, 03:51 PM   #6
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Re: LS wiring Harness layout

The main starter wire follows the oil pan from starter to balancer, then across to the drivers side, and up to a red connection that bolts to the front accessory mount. The top part of the harness forms a "U" on top of the engine (it's actually an "n" if you're standing in front of the engine), with the coil and injector plugs parallel to each other. The cam position and oil sensor are in the back. Trans connections branch off at head 7 (drivers rear) close to these. AC , coolant level, and passenger O2 are the longest leads, and branch from the "n" about head 8(passenger rear). If I remember correctly, the oil pressure and cam position are unique plugs - you cannot find another sensor that uses the same plug type. Worst case, lay the two groups of injector plugs parallel to each other. These two groups of four connect to each other at the rear of the engine.
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Old 08-15-2017, 04:52 PM   #7
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Re: LS wiring Harness layout

Front to the left.

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Old 08-15-2017, 05:09 PM   #8
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Re: LS wiring Harness layout

Nice! Is this 2002, or newer? I don't know when they switched to three connectors on the ECM. 2001 only had two.
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Old 08-15-2017, 05:31 PM   #9
67 chevelle
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Re: LS wiring Harness layout

photobucket sucks now


I have a picture for you anyone have a clue how i can get it to you ?
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Old 08-15-2017, 05:48 PM   #10
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Re: LS wiring Harness layout

figured it out , just put it in my album on here
the harness above is for like 2015 and newer

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58 Apache fleet , 235 , offy intake , dual exhaust , 4 on the floor , red/white
69 Long Fleet , Custom , 6.0, 4l60 , AC , Medium Olive

Last edited by 67 chevelle; 08-15-2017 at 06:31 PM.
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