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Current Performance Wiring is proud to be of service since 1999
6330 Pine Hill Rd #16 • Port Richey, FL 34668

The S-10 trucks are a very popular vehicle for engine swaps of all kinds. Since our specialty is with these trucks, there are many variations offered to install a fuel injected chevy small block engine in any year truck. Below you will find a list of years and options that will make a bit of difference in the harness, as well as some information you will need to help make better decisions for your swap. Please be sure and read the extra information supplied in each year for certain things that you may or may not be aware of.

When disconnecting the stock vehicle harness, all you will need to do is unplug it from any connections at the firewall, fenders, and anywhere else that a connector may be. The new harness should simply plug back in to any connectors, there should be no reason to remove or replace anything from the inside of the vehicle in most cases.

1982-1993

This is the original "square" body style S-truck. The blazer kept the square body style even through '94. There are many variations between these years as far as the computers and wiring goes, but nothing major. Certain things that matter are whether or not the truck was a 4 cyl, 2.8L 6 cyl., or a 4.3 V6. This will affect how the wiring must be done in order for the truck to function properly after the engine swap.

These year trucks can have the tachometer recalibrated for the V8 so they will read properly. Also available is a tachometer recalibration module which can be added in to the harness and will recalibrate the signal from the engine's computer so the stock truck tach will read properly. Of course, you can always use an aftermarket tachometer that is calibrated for a V8 and avoid any of these extra pieces or hassles.

1994 and 1995...
Things YOU will need to know...

First and foremost... we only build wiring harnesses for 94-up LT, LS, and Vortec engines. We DO NOT do wiring for TPI or Carburated engines in to any of these trucks.

The trucks that came with a PCM mounted on the overflow bottle under the hood will require both the stock truck computer and the ECM from the new engine if you are installing an LT1, but not always with the LS1 engine, if you intend to keep the ABS and Cruise Control. When complete, the stock truck computer will control things like the cruise control, ABS, speedo, etc. The computer for the engine will pretty much just run the engine and control the electric fans. If the computer is mounted under the dash from the factory, than that computer can be completely replaced with the LT1 or LS1 computer and all factory vehicle functions can still be maintained.

The A/C is usually wired directly using the V6 trucks existing Low Pressure switch on the dryer. The 4 cyl trucks will require that a Low Pressure switch be added, the easiest way is to simply swap the 2.2L A/C dryer with that of a 4.3, it will thread right back in to the A/C lines.
Alternatively, you can use the LT1 or LS1 computer to run the A/C which will bump up the idle, and switch the fans on automatically. This method will require the LT1 or LS1 vehicles pressure sensor be installed in the High Pressure side of the A/C lines, and, in the case of the LT1, a temperature sensor would need to be installed in the coil. This way is not used much because of all the extra hassle, and it doesn't really make that big of a difference anyway.

In our custom harness there will be 2 extra relays mounted on the firewall next to the existing 4 that are there now. The existing 4 relays on the 94 & 95 truck control the A/C compressor, blower motor, starter, and 3rd brake light. The extra 2would be the fan relays. All 6 relays will be wired properly in the new harness from Current Performance and simply go right back on to the firewall, the original 4 relays themselves actually stay on the firewall, just simply unplug the connector. The new harness will come with connectors that plug back in to the relays left behind. The 2 additional relays will have brackets to mount them next to the existing 4.

A 2nd Data Link Connector (DLC / ALDL) will be included in the LT1 and LS1 harness. A hole can be drilled and the wires fed through in to the cab, and then the connector can be mounted somewhere inside. Alternatively you can leave the DLC loose in the engine compartment, but anytime a scan tool is plugged in, you will not have direct access from inside the passenger compartment.

The 94-95 trucks can have the tachometer recalibrated for the V8 so they will read properly. Also available is a tachometer recalibration module which can be added in to the harness and will recalibrate the signal from the engine's computer so the stock truck tach will read properly. Of course, you can always use an aftermarket tachometer and avoid any of these extra pieces or hassles.

A typical harness for the LT1 swap in a 94/95 S-10 ranges from $750-$795
LSx & Gen III Vortec harnesses are typically $850

*Ask about our sensor package including MAF and O2 sensors for a complete matched system.

1996 and 1997...
Things YOU will need to know...

First and foremost... we only build wiring harnesses for 94-up LT, LS, and Vortec engines. We DO NOT do wiring for TPI or Carburated engines in to any of these trucks.

The 6 cyl trucks for 96-97 will require both the stock truck computer and the ECM from the engine if you are installing an LT1 engine. When complete, the stock truck computer will control things like the cruise control, ABS, speedo, etc. The computer for the engine will pretty much just run the engine and control the electric fans. Sometimes depending on the truck and what options it has, an LS1 swap can run just the LS1 computer to do everything, and completely replace the original truck computer. If you are installing a Vortec 5.0L or 5.7L motor, the stock V6 computer can be reprogrammed to work properly.
The 4 cyl trucks of these years do not always require that the stock truck computer be kept, although different situations may require that the stock computer remain.

The '96 and '97 trucks are probably the biggest pain to build a harness for, this seemed to be transition years for GM while they figured out what worked and what didn't. The '96 model has an ABS control under the hood that is only used in '96. This system is controlled by the stock truck computer and the wiring runs through the engine harness, whereas most other years have a separate computer and harness to control the ABS.
The '97 truck uses the same computer as the '96, but it has a separate computer that controls the ABS which is a different unit than the '96. The '97 truck needs the 5th (small) connector from the stock harness retained when the stock truck computer is kept. This connector can simply be removed from the stock harness and plugged in when the new harness arrives. The 5th connector has a single wire in it that simply loops around from one hole to another and pretty much does nothing except tell the computer that it's there.

The A/C is usually wired directly using the V6 trucks existing Low Pressure switch on the dryer. The 4 cyl trucks will require that a Low Pressure switch be added, the easiest way is to simply swap the 2.2L A/C dryer with that of a 4.3, it will thread right back in to the A/C lines.
Alternatively, you can use the LT1 or LS1 computer to run the A/C which will bump up the idle, and switch the fans on automatically. This method will require the LT1 or LS1 vehicles pressure sensor be installed in the High Pressure side of the A/C lines, and, in the case of the LT1, a temperature sensor would need to be installed in the coil. This way is not used much because of all the extra hassle, and it doesn't really make that big of a difference anyway.

In our custom harness there will be 2 extra relays mounted on the firewall next to the existing 4 that are there now. The existing 4 relays on the 96 & 97 truck control the A/C compressor, blower motor, starter, and 3rd brake light. The extra 2 are electric fan relays. 4 relays will be wired properly in the new harness from Current Performance and simply go right back on to the firewall, the original 4 relays themselves actually stay on the firewall, just simply unplug the connectors from the 2 that are a part of the engine harness (starter and A/C compressor). The new harness will come with connectors that plug back in to the relays left behind. The 2 additional relays will have brackets to mount them next to the existing 4.

A 2nd Data Link Connector (DLC / ALDL) will usually be included in the LT1 harness. A hole can be drilled and the wires fed through in to the cab, and then the connector can be mounted somehwere inside. Alternatively you can leave the DLC loose in the engine compartment, but anytime a scan tool is plugged in, you will not have direct access from inside the passenger compartment.

The 96-97 trucks can have the tachometer recalibrated for the V8 so they will read properly. Also available is a tachometer recalibration module which can be added in to the harness and will recalibrate the signal from the engine's computer so the stock truck tach will read properly. Of course, you can always use an aftermarket tachometer and avoid any of these extra pieces or hassles.

A typical harness for the LT1 swap in a 94/95 S-10 ranges from $750-$795
LSx & Gen III Vortec harnesses are typically $850

*Ask about our sensor package including MAF and O2 sensors for a complete matched system.

LS1/T56 harness for a 97 2.2L S-10 - No Splicing - built from scratch - ready to install

1998 and newer...

Things YOU will need to know...

First and foremost... we only build wiring harnesses for 94-up LT, LS, and Vortec engines. We DO NOT do wiring for TPI or Carburated engines in to any of these trucks.

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.

The trucks that came with a PCM mounted on the overflow bottle under the hood will require both the stock truck computer and the ECM from the engine IF you are installing an LT1 engine AND you intend to keep all of the factory truck functions. Issues with swapping from a 2.2L to an LT1/4 exist, but are not impossible to overcome. A 96-97 LT1 engine is recommended.
Is all of this required for us to build you a harness?? No.

When complete, the stock truck computer will control things like the cruise control, ABS, speedo, etc. The computer for the engine will pretty much just run the engine and control the electric fans.

If you are installing a Vortec 5.0L or 5.7L motor, the stock computer can be reprogrammed to work properly.
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.

In LT1 harnesses, the A/C is usually wired directly using the V6 trucks existing Low Pressure switch on the dryer. The 4 cyl trucks usually end up needing a Low Pressure switch for the A/C instead of the pressure sensor that is used from the factory, the easiest way is to simply swap the 2.2L A/C dryer with that of a 4.3. The dryer and Low Pressure switch can be bought at your local dealership parts counter.
Alternatively, with the LT1 swap, you can use the LT1 computer to run the A/C which will bump up the idle, and switch the fans on automatically. This method will require the LT1 vehicles pressure sensor be installed in the High Pressure side of the A/C lines, and the temperature sensor would need to be installed in the coil. This way is not used much, and it doesn't really make that big of a difference anyway.

A 2nd Data Link Connector (DLC / ALDL) will usually be included in the LT1 harness. A hole can be drilled and the wires fed through in to the cab, and then the connector can be mounted somehwere inside. Alternatively you can leave the DLC loose in the engine compartment, but anytime a scan tool is plugged in, you will not have direct access from inside the passenger compartment.

The 98-newer trucks can NOT have the tachometer recalibrated for the V8 (LT1 swaps mainly). The only available solution we have found is a tachometer recalibration module which can be added in to the harness and will recalibrate the signal from the engine's computer so the stock truck tach will read properly. Of course, you can always use an aftermarket tachometer and avoid any of these extra pieces or hassles. This is NOT an issue with LS1 swaps. The LS1 tach signal is interpreted properly by the 98-up S-truck gauges and the tachometer reads correctly

A typical harness for the LT1 swap in a 94/95 S-10 ranges from $750-$795
LSx & Gen III Vortec harnesses are typically $850 .

*Ask about our sensor package including MAF and O2 sensors for a complete matched system.

I know this might be some tough reading, so please feel free to call or email if you have any questions.



LS1/4L60E harness for an '01 4.3L S-10 - No Splicing - built from scratch - ready to install

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