03 with 72 body

turbostang7

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Apr 11, 2011
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I just picked up an 03 duramax that was in need of some TLC, ecsb, what I am thinking I want to do is put a 72ish body on this frame and make it a single cab short bed. I know this has been done several times and I have looked at several threads but have a few questions about it.
1. I want the interior of the truck to apear completely as a 72, but want the AC, cruise etc to still work. I don't want the steering column or gauge cluster. Can these be removed and still have the rest work? Any ideas on this

2. I don't believe I need a standalone as the entire truck is there and I still want ABS and everything to function normally, any thoughts? I think this also ties into the previous question on the column and cluster delete. I could possibly even splice in to the factory power windows and door locks and make those work in the older truck.

I want to tie the wait to start light to a factory idiot light and make that work and get a check engine light the same way. And an OBD port hidden somewhat under the dash

Gauges shouldn't be a huge problem to make work just put sending units in off of the older motor and wire up basically. Only issue I see is figuring the tach and cable driven speedo out on the factory gauges but that shouldn't be a huge hurdle.

Anything I am missing on the electrical side? The fab side I will figure out as I go, plan on using the radiator and CAC out of the 03 as well as most of the core support modded to fit the older body.
 

turbostang7

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duratothemax

<--- slippery roads
Aug 28, 2006
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I just picked up an 03 duramax that was in need of some TLC, ecsb, what I am thinking I want to do is put a 72ish body on this frame and make it a single cab short bed. I know this has been done several times and I have looked at several threads but have a few questions about it.
1. I want the interior of the truck to apear completely as a 72, but want the AC, cruise etc to still work. I don't want the steering column or gauge cluster. Can these be removed and still have the rest work? Any ideas on this

2. I don't believe I need a standalone as the entire truck is there and I still want ABS and everything to function normally, any thoughts? I think this also ties into the previous question on the column and cluster delete. I could possibly even splice in to the factory power windows and door locks and make those work in the older truck.

I want to tie the wait to start light to a factory idiot light and make that work and get a check engine light the same way. And an OBD port hidden somewhat under the dash

Gauges shouldn't be a huge problem to make work just put sending units in off of the older motor and wire up basically. Only issue I see is figuring the tach and cable driven speedo out on the factory gauges but that shouldn't be a huge hurdle.

Anything I am missing on the electrical side? The fab side I will figure out as I go, plan on using the radiator and CAC out of the 03 as well as most of the core support modded to fit the older body.

I would suggest grabbing some wiring diagrams and going to work. You are going to have to do quite a bit of work to pare down the harness and make it simpler, but still keep ABS and all that.

100% possible. But its going to be a lot more work than you are thinking...

You cant just "splice into the power windows and locks" because those are controlled via the databus on the 2003. I mean you could, but again, its going to take a LOT of wiring diagram studying, and you'll have to use the 2003 window/door switches.
 

turbostang7

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Thanks for the info. So would it be easiest to just swap the entire harness into the older truck, hide the cluster under the dash somewhere, and just live with the column? The power windows and whatnot aren't that critical as retrofit kits are cheap and easy to install on those old trucks.

I'm assuming it would be possible to hide he dash and pggyback off of he lights for the wait to start/check engine and run them to one of the idiot lights?
 

THEFERMANATOR

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whats wrong with using the cluster and column I think they look really nice in the older trucks lol

The new cluster and column against an old style dash doesnt look so hot to me. The columb isn't needed to make any of it work. The downfall to keeping abs without the cluster is there is no way to have a warning light without the cluster. Pretty sure those are class 2 databus specific. I'm sure somebody could build you an interface to control a abs/brake warning light, but it would be a 1 off setup. If you add in the new style cluster but stay old style dash, you would be stuck with airbag warnings from the dic since it wouldn't receive any messages from it. Tach, speedo, check engine, and wait to start are already on dedicated circuits. You can always run a manual climate control os, and use an old school ac setup integrated through the ecm for it to control. Cruise already has dedicated inputs to the ecm for lb7, so no problems there. Like Ben said, its all doable, you just have to decide how in depth you want to get.

I would go stand alone from the sound of what you're after, and then go with an abs system from a gmt-400 truck. It will read the front wheel speed sensors perfectly fine with no issues, the ecm outputs the required 128,000 ppm signal the older abs requires for rear speed sensor signal, and it can work via a hard wired indicator light so it doesn't require a cluster for a warning indicator. One off of a gmt-455 3500hd is very similiar, but is calibrated for 4 wheel disc brakes.
 

turbostang7

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The gmt-400 route might be the way to blog to keep the ABS.
In order to delete the column doesn't the ECM need to see a resistance from there or would bypassing the VATS get rid of it needing to see that?
Doing a standalone would cure most of these issues anyways especially with the older abs in place.

Another option I was thinking about is swapping the harness from the 03 into my 02 for the future LBZ swap to make it easier. I was going to swap most of the interior anyways as it has the charcoal interior that I like better than the light grey.
Would dealing with the older 02 electronics make any of these ideas easier or just as difficult?
 

THEFERMANATOR

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IMO 01-02 is a little more stand alone friendly. The column is not needed as a quick change in EFILIVE can bypass VATS, OR you could keep it if you really wanted to. If you keep a BCM i nthe truck, you can install a simple resistor across the BCM key signal feeds, and by pass it that way. Or you could swap out to an ignition switch out of a GMT-400, and put it in your dash if you really wanted VATS. Mines been running stand alone in my 95 BURB for over 6 years now.
 

Madspeed

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Mar 22, 2007
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Elk Ridge Utah
You certainly can do all of what you requested as others have said "if you work for it"
I did my 72 Blazer in 2007 with abs, power windows and locks, ac (working off the factory 72 controlls)
you could 1 strip down a cluster to the board hide it under the dash and pull wires up with bulbs to work all the lights you want.
2 get a Cable X speedo converter from digital to analog.
3 use 75 ish van power window motors and regs with mods and keep the wing vent.
4 use a rare cruise stalk from a 72 ish and have everything but accelerate.
Tach I havent tackled yet but I will probably buy dakota digital's can bus system ( They have guages that will interface w my 01)
 

turbostang7

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Good to know, it's nice that others have tried this and I'm not shooting in he dark. Everyone I work with thinks I'm nuts lol.
I honestly don't think it's that hard, time consuming yes but not hard. But the reward of driving something that rides nice and looks great is worth it.
As a minor update I have possibly been persuaded by the better half to find a blazer to put on the frame as they will have enough seats for the whole family. So the search for a body starts over....