Why does the harness have to be modified?
Thread Starter
Joined: Oct 2008
Posts: 313
Likes: 5
From: Mississippi Gulf Coast
Why does the harness have to be modified? I'm sure theres a good reason (or 12) but I'm curious as to why a stock harness must be modified for a hybrid. If it physically fits your application where do the problems arise?
BTW, I have an '05 Silverado harness (DBW throttle body) and PCM for my street rod and I'm trying to decide if I want to just sell it and buy an stand alone harness or pay to have this one modified.
BTW, I have an '05 Silverado harness (DBW throttle body) and PCM for my street rod and I'm trying to decide if I want to just sell it and buy an stand alone harness or pay to have this one modified.
The OEM harness is designed to be connected and intergrated with other harnes (Body, Brakes, Cruise Control, other emssions and function.
Without those other harness connected and giving inputs, then Engine and PCM will not function. By modifying the harness. You can do away with the other harness (BCM and others).
You really only need a few mods to the harness to turn it into a Standalone harness, +12v battery, +12v Ign. and Grounds.
The other you can get around, but you may as well use then; Fuel pump, Serial (ODBII connector), Fan Relays, Tach, VSS output and a few others that are handy to be using, but you can get around them by using standalone system, the Fuel system is one, and a Standalone Fan/relay is another.
Intergrading a fuse box is also a good idea.
but as you stated, there are about a dozen other reason and work arounds. But unless your removing many other wiring system and harness the un-modified engine wiring and PCM will not fire up..
VATS is another item you need to work around with, it requires the BCM system along with the Steering Column and Key.
Without those other harness connected and giving inputs, then Engine and PCM will not function. By modifying the harness. You can do away with the other harness (BCM and others).
You really only need a few mods to the harness to turn it into a Standalone harness, +12v battery, +12v Ign. and Grounds.
The other you can get around, but you may as well use then; Fuel pump, Serial (ODBII connector), Fan Relays, Tach, VSS output and a few others that are handy to be using, but you can get around them by using standalone system, the Fuel system is one, and a Standalone Fan/relay is another.
Intergrading a fuse box is also a good idea.
but as you stated, there are about a dozen other reason and work arounds. But unless your removing many other wiring system and harness the un-modified engine wiring and PCM will not fire up..
VATS is another item you need to work around with, it requires the BCM system along with the Steering Column and Key.
Thread Starter
Joined: Oct 2008
Posts: 313
Likes: 5
From: Mississippi Gulf Coast
Thanks for the quick and thorough reply. Guess I better start saving up for a harness.
Think I should have this one modded or buy a pre-fabbed harness?
Think I should have this one modded or buy a pre-fabbed harness?
If you have the time and a bit of skills.. (soldering, splicing, etc). and reading the FAQ for wring and pin assignements.. you can do it yourself. But look around, you can sometime fine pre-modified harness or someone that will help out and do it for a good price.
If you can afford it, Speartech (John), Current performance, Wait4meperformance (Jesse) and other vendors do a great job of mod'in them and working to intergrade them with your cars systems or selling you a new one.
Either way.. they usually work ok.
If you can afford it, Speartech (John), Current performance, Wait4meperformance (Jesse) and other vendors do a great job of mod'in them and working to intergrade them with your cars systems or selling you a new one.
Either way.. they usually work ok.
huh?
we take the stock harness and either leave everything in there or take out some of the things we are not going to use, ie A/C, EGR/AIR, etc and then hook up <10 wires and run them all day long after PCM programming.
we take the stock harness and either leave everything in there or take out some of the things we are not going to use, ie A/C, EGR/AIR, etc and then hook up <10 wires and run them all day long after PCM programming.
Thread Starter
Joined: Oct 2008
Posts: 313
Likes: 5
From: Mississippi Gulf Coast
Are you saying that PCM programming (to delete stuff you're not using) is all you do to make 'em work?
Richard
That's what we do. Turn off VATS, make what ever other changes we want in the tune, hook up the few wires for ground, ignition, 12V, FP relay and turn the key, fires up.
VATS removal is one of the biggest keys here....
VATS removal is one of the biggest keys here....
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That is what I stated in my 1st reply post to him..
Shon Herron ... are you a vendor or a shop that provides these services ?.. if so.. what are your cost for modifying a harness to standalone and for a basic Mail order tune/flash ?
Shon Herron ... are you a vendor or a shop that provides these services ?.. if so.. what are your cost for modifying a harness to standalone and for a basic Mail order tune/flash ?
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I'm sure theres a good reason (or 12) but I'm curious as to why a stock harness must be modified for a hybrid. If it physically fits your application where do the problems arise?
BTW, I have an '05 Silverado harness (DBW throttle body) and PCM for my street rod and I'm trying to decide if I want to just sell it and buy an stand alone harness or pay to have this one modified.
BTW, I have an '05 Silverado harness (DBW throttle body) and PCM for my street rod and I'm trying to decide if I want to just sell it and buy an stand alone harness or pay to have this one modified.
honestly the harness is not that hard to do, also if you dont want to theres a guy on ebay that does then for a cheap price, and also tunes your pcm while hes at it. its like $200 bucks and he does a great job.
Here's what I did, got everything running w/ the harness the way it came out of the car, '04 GTO, had the PCM programmed to remove the emissions stuff other than the first set of O2 sensors. Pretty easy, few power wires, ground, and fuel pump relay... = VROOM.
From there I removed the connectors I didn't need anymore, along w/ most of the wires. I left around 6" of each wire as a "just in case". Then rewrapped the harness and re-added the corrugated tubing.
From there I removed the connectors I didn't need anymore, along w/ most of the wires. I left around 6" of each wire as a "just in case". Then rewrapped the harness and re-added the corrugated tubing.
This, my gf said "it looks a whole lot better". It's just more aesthetically pleasing when you get all of the vestigial stuff out of the harness and maybe run things in a different way from factory to make it neater.
We used our '99 FBody harness as is. You can un-wrap the harness and remove wires if you want to, but you risk removing the wrong wire(s) and / or damage to needed wires from flexing the harness, etc. If you use dual fans, A/C, EVAP system, most of the wires are used anyway. Our installation deleted the EGR and AIR systems.
TECH Resident
Joined: Nov 2007
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From: Texas
We used our '99 FBody harness as is. You can un-wrap the harness and remove wires if you want to, but you risk removing the wrong wire(s) and / or damage to needed wires from flexing the harness, etc. If you use dual fans, A/C, EVAP system, most of the wires are used anyway. Our installation deleted the EGR and AIR systems.
