Description
This harness is standalone and is not intended to replace the OEM engine wiring. Standalone harnesses are intended to run the designated engine & transmission only, generally when swapped into another vehicle.
Painless LS swap wiring harnesses make getting your engine swap wired a simple task!
This harness is designed for use on the 2003-2006 4.8L, 5.3L, and 6.0L throttle by-wire engines with a 4L60E, 4L65E, 4L70E, 4L80E, 4L85E, or manual transmission. These engines were found in factory 2003-2006 Vortec Trucks. Engine codes supported are LR4, LM7, LM4, LQ4 and LQ9. This harness will support flex fuel and nonflex fuel engines. Flex fuel engines will require an inline fuel composition sensor to run E85 fuel. Included with this harness is a 10-circuit weatherproof fuse block & mounting bracket and GM color-coded wires with labels for easy installation.
This standard-length harness allows four feet from the back of the intake manifold to where the fuse block and ECM mount. Perfect for those who plan to mount these components under the dash or in the glove box.
This kit includes:
- All new fuel injection harnesses with OEM fitment connectors and harness breakouts
- OBDII connector, mounting bracket, and check engine light
- Crimp-on terminals, rubber grommet
- Mounting hardware
This harness will not work with 2006 accelerator pedals and ships with connectors for 2003-2005 5.3L oxygen sensors. We recommend checking the online manual for the full list of required mating parts prior to ordering.


