bud8fan, yes I got the harness all the way up to the firewall and the pedal assembly. but I didn't get the body control module under the dash which works with the tow/haul switch along with every other electrical device on the truck.

Red, yea I was leaning to just wiring the ac up with out the computer but I was just worried about the idle up it does when the ac is on. On the tow haul... yea I need it this truck tows a boat just about every weekend. I have to double check but I don't think the silverados shifter has the option for taking it out of overdrive. I think it just has PRD21 I think.... Thanks for your replies. Let me know if you have any other thoughts.