This stand alone fuel injection wiring harness fits GM vehicles from 2003 to 2006. It is designed to work with 4.8L, 5.3L, 6.0L throttle by wire engines with a 4L60E, 4L65E, 4L70E, 4L80E, 4L85E, or manual transmission. Engine codes supported are LR4, LM7, LM4, LQ4 and LQ9. 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 fuseblock and ECM mount. Perfect for those that plan to mount these components under the dash or in the glove box. We recommend checking the online instruction manual to determine all the required mating parts prior to installation.