LS Swap - routing all the stuff along and on the frame. wiring harness suggestions?

[Slowguy]

I am trying to keep everything clean and organized by doing it now while everything is off the frame. I'll have to stop on some things until I at least get the cab set back in place but I'd like to stay ahead of it as much as possible.

I routed the fuel lines to the rear tank, air lines to the air bags, wiring to the level sensors, alternator line, battery cable to the side frame mount battery and the rear brake line.

I'm wondering what's the cheapest and most complete option for my main wiring harness (i.e painless wiring). I assume most of these kits are designed for everything factory? I don't want to purchase a $600 wiring kit thinking I need it only to find I'll only use part of it.

I already purchased a ls kit and it includes the stuff to connect to the starter, alternator, all engine sensors and components, fuel pump, trans, and pcm. So I also plan to get a dakota digital speedo and vintage air ac/heat.

As I understand it, (thinking off the top of my head), this means I will need the wiring to all the lights, cab controls, and a fuse center? Not sure I will need much. Figured I'd as to see if someone has something similar and could suggest.

[MDPotter]

I used the American Autowire classic update kit. There is wiring that you will not use since you have an LS, but still most of it. I actually used most of the accessory circuits to power the LS harness to keep things a little cleaner (no standalone fuse center like most LS harnesses). You still need wiring for front lighting, rear lighting, gauges, heat/AC, radio, wiper motor, courtesy lights, etc.

[LS short box]

I used Painless universal kits a few times with good results on my LS swaps. Cheaper than the original type wiring harness. You will have a few extra wires depending if you have AC, power windows and such. Save your old wiring harness you will need the old connectors for things like the heater.

[Jolin]

I am at the same spot in my build as Slowguy, LQ4 4L80e, LS harness and an American harness kit. MDPotter could you provide a little more detail? I think I can combine a few things but not sure. thanks

[Slowguy]

Jolin-

I can take pics of anything you need if it might help you. Right now I'm trying to figure out what the three wires at the fuel pump are for. One is a ground and the other two are on the connector that goes into the pump.

[Mbeef61]

Subscribed. Also doing the same thing soon. Leaning towards American auto wire

[Chvy2NV]

Subd. I’ll be doing the same soon. Where are you guys mounting your ECM’s and all other LS stuff
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[Slowguy]

I think I may put the fuse block from the ls harness on the firewall or beneath the dash somewhere. If the wire is long enough, I'd like to tuck away the pcm. Probably beneath the dash somewhere as well.

[MDPotter]

Originally Posted by Jolin

I am at the same spot in my build as Slowguy, LQ4 4L80e, LS harness and an American harness kit. MDPotter could you provide a little more detail? I think I can combine a few things but not sure. thanks

There's more info in my 68 build thread, but here are a few details from what I did:
-I reworked my LS harness myself. Consolidated all the pink (keyed power) wires which include injectors, coils, sensors, etc. and merged them into a few wires which I then routed through a firewall bulkhead I bought from American Autowire. From there, attached wire inside the cab to a buss bar. Power for this buss bar came from one of the 30A keyed power accessory circuits from the American Autowire chassis harness.
-Consolidated all the orange (constant power) wires and ran them under the carpet from the PCM to an Autowire battery feed accessory circuit.
-Extended all wires from the LS harness that run to the PCM so that I could run that main branch of wiring down the transmission, through the trans tunnel, and into my center console. I put the PCM and OBDII port in the console where it's dry and hidden.
-I don't have a separate fuse block for the LS harness. It's cleaner to use the accessory circuits from American Autowire to power that harness.
-The only fuse block I have outside of the Autowire is for my fans and fuel pump in the engine bay.

Any specific questions, let me know.

[Twisted78SS]

subscribing..

I am doing a good bit of my cab wiring now as well, I am using the AAW Classic Update kit.
It will have to play nice with the Dakota HDX wiring and my LS3 harness.

As mentioned, I may not use all the AAW kit, but it does have several extra fused leads included to power most of what I need.

[derotoreut]

I'm close in finishing up my LM7 5.3 swap. I used AAW classic update kit. I've used Painless in the past and IMO it is anything but painless when compared to AAW. If you are smoothing the firewall then you may not want the classic update kit. Might be better off with AAW Highway kit. I'm using the classic update kit for my K10, but my 71 C10 will use the AAW Highway 22 kit.

I located my PCM under the passenger bucket, which I put Blazer tilt brackets on so I can easily access the PCM if needed. I'm using Dakota Digital RTX system, which I just finished the install. I'm also installing Vintage Air. You can check out my K10 build thread.

[Slowguy]

So something like this?

https://www.americanautowire.com/shop/highway-22-plus-universal-wiring-system

Call me weird but I find wiring frustrating and satisfying at the same time. Such a good feeling when it looks nice (and) works correctly!
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[LS short box]

I put my ECM and relays behind the glove box. I had to notch the glove box paper board a bit to clear the ECM. The fuse block and adl connector I just screwed them to the heater box. You can just see the check engine light when sitting in the truck but you can't see anything standing outside.