03 sierra 4.3 to 5.3 swap(i need help)

[Frenchy]

You have to use an 03+ harness, because yes, there is differences.

[sonnychills]

I repined the plug as pictured at the beginning of this thread to match each other. I also had to put a neutral safety switch plug on the harness since it had been cut off. So basically I have to get an 03+ harness and dbw stuff as well?