How many wires need to be hooked up to get a factory harness running?
 

If i pickup a complete 5.3 from a wrecker (2001+) how many wires need to be hooked up from the factory harness to get it running? I always read with standalone harness 'sor after market systems that they only require 3 wires to be hooked up to run. Is the factory harness bad in its stock form?
Thanks

All pinks go to switched ignition. PCM orange wires go to battery. Hot wired fuel pump and it will start after PCM file has vats deleted. Obviously you should use fuses, relays and other mods if you want it to be safe and reliable. But that's all that's needed to test the engine to see if it has any mechanical issues.

^^^ What he said ^^^ I know it can be scary when you look at it all in a pile, but it is really pretty easy to get one fired up. You will also want to wire up another ALDL connector. Its only a couple wires from the PCM, I just cant remember which ones off the top of my head.

Factory harness = lots of work
I did the harness mod myself and used the money I saved to get HP tuners. Oh top of saving money you will learn a lot about your engine and it's modern control system that really comes in handy. If you aren't pressed for time I would definitely recommend doing the work yourself.

its not too hard lt1swap has wiring info and diagrams if you have the fuse box itll be alot easier

just keep track of what pins you delete in case you change your plans down the road.

ask me how i know. doh!