I usually tap the green wire with the white stripe. This goes to the connector that plugs into the very back of the compressor (can be seen laying under the truck on the passenger's side). If your trying to find the keyed power wire take off the fise box cover then lift up the part that has the fuses so you can see the wires under it. Your going to see 6 "blocks" of fuses. Look to the far right column of the center block and count down 9. There should be a pink wire there. That's the wire you want!

Tom
i got this off the silverado ss sight

 

Thanks Tom I'm going to try it on Sunday. I'll let you now which one I used.

 

I would pull the fuse block up, there is a clip next to the fender you can pull out, and the fuse block pivots up. Find a wire under there. Lots to choose from. I think I used a pink one in the middle section. Mine was divided into 3 sections front to back.

 

Thanks everyone with helping me. I got under the fuse box and found three pink wire's that were 3 into one. I taped one of those and works good...Thanks to all