Description
Engine Computer (ECU) and/or programming sold separately
1998 trucks and all 99-2000 V6 trucks will require purchase of additional C101 Body connector adapter:
98-2000 S10 C101 Adapter
Current website ordering is for Blue/Red and Blue/Green 24x ECUs. For 58x engines please call or email for information.
The available options provide selections of harnesses for the S10 LSx swap. This harness configuration leaves the ECM in the stock location on the overflow tank under the hood.
Custom orders can be built if your installation does not fall under the above selections.
- All of our S/T Truck LS swap harnesses include wiring for A/C, Starter, factory gauges, and ABS. All factory functions of the truck can be retained with this product. Wiring and relays for electric fans are also included.
- Al of our S-series LS swap harnesses include relays and wiring for electric fans that draw under 30 amps. If a higher amperage fan is being used, you may consider adding our HD Fan module to your order.
- The “truck intake” variation of these harnesses are configured with standard Multec 2 style injector connections. If you have Flex Fuel injectors, or any other variation, you will either need a harness made for your application, or purchase adapters for the different injectors. LS1 style intakes will have EV1 style connections.
- All harnesses are configured with 5 wire MAF connectors intended to work with MAF p/n AF10043 or equivalent.
- Most harnesses are configured with flat 4 pin truck style oxygen sensors intended to work with Bosch p/n 13026 or equivalent. The only exception is a 4 cylinder truck that had a manual transmission going to an LS1 w/ manual transmission using an F-body ECU. These will use 1999-2002 F-body O2 sensors.
- Most variations of this harness will require the 4.3L V6 accumulator and low pressure switch to be used instead of the 2.2L I4 high pressure switch. The only exception is a 4 cylinder truck that had a manual transmission going to an LS1 w/ manual transmission using an F-body ECU.
- Cable throttle harnesses are intended to work with the 1999-2002 Blue/Red connector style ECUs while the electronic throttle harnesses are meant to work with the 2003-later Blue/Green connector style ECUs
As ordered online, all S10 harnesses come with all wiring for full emissions compliance as well as electric fans.
Direct-Fit LSx/LT/Vortec for 1982-2004 Chevy S-10/ Blazer, GMC Sonoma / S-15/ Jimmy / Isuzu Hombre
Our Direct-Fit custom wiring harnesses are plug-and-play, custom built, and designed specifically for your project utilizing a 97-up LSx or Vortec small block V8 engine. Each harness is built from scratch specifically for the application listed. In most cases a Direct-Fit harness will allow you to retain all of the factory vehicle functions and gauges after the engine swap. Cable throttle harnesses are intended to work with the 1999-2002 Blue/Red connector style ECUs while the electronic throttle harnesses are meant to work with the 2003-later Blue/Green connector style ECUs.
The main difference between our Direct-Fit harnesses and a standalone engine management harness is that a standalone engine management harness is designed to do nothing except run the engine, and supply any necessary outputs such as speedometer and tachometer. Our Direct-Fit harness is built to include all of the functions that your vehicle will use, such as original gauges, any connectors that go to or through the firewall, relays to control the fans via the computer, and we will utilize the factory Neutral Safety switch when possible.
A Direct-Fit custom harness from Current Performance Wiring contains all of the electrical connections that are required for the vehicle that you are installing the new engine into. These harnesses include all necessary body connections to directly replace your original 4.3L or 2.2L engine harness and properly operate the new engine and transmission as if it all came directly from GM that way.
This harness is not only designed to plug right in to the project vehicle and engine, but since they are completely built from scratch, they can be made to your specs. If you are going for a clean install and want the ECU inside the passenger compartment, or all the way back in the trunk, we can make it exactly how you need, or if you are happy with things just how they were, we have inventory harnesses that will set the ECU back in it’s stock location on the overflow tank and take care of all your needs.
Direct-Fit Custom Harnesses come covered in standard OE split loom but optional Braided loom is available for an extra charge.
1998 and newer… Things you will need to know…
In 1998 GM redesigned the interior of the S trucks, and made a new grille. To most people, this is pretty much the extent of what they know. On our end of the world, the Electrical system of the 98 and up trucks is VASTLY different from prior years. One main difference you will notice is the Underhood Bussed Electrical Center (UBEC) located in front of the ABS module on the Driver’s side fender. This box contains most of the relays and fuses for the engine components. This makes wiring in a new engine a bit easier because at least most of the power feeds and relay controls go to one central location.
If you are installing any of the LSx or Gen III Vortec engines (4.8, 5.3, 6.0, or 6.2L) We have developed a program that will allow just the LSx computer to be used in a 98 and up S-truck. This single computer will control the engine, allow the gauges (including tachometer) and ABS to work properly, control the electric fans, and control all other functions of the truck just like factory.
There will be 2 extra relays to be mounted on the firewall next to the existing 1 that is there now to control the electric fans.
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LSx & Gen III Vortec harnesses start at $850
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LS2/LS3/LS7/LS9 & Gen IV Vortec harnesses start at $850





