I got my harness in from allen for Ls1 fans for my 02 Denali. I hooked it all up. and nothing happened. The blue wire that goes to the computer I took that out and touched it to the ground and both fans came on, so i know its not the harness. I still have my stock pcm, but I figuered it would just work. I am now being told it won't. I have orderd a Nelson tune and I am just waiting for it to get here. Now my other question is the green wire!! which one do I use?? I have a light green, dark green, and a light green with a white stripe.