Making a 2002 5.3 in 2006 Silverado

[nigilroyboy95]

How can I make the engine,trans, computer, and engine harness from a 2002 Chevy Silverado work in a 2006 Silverado. Both had 5.3s I've got it all hooked up but as soon as I turn the key first click it starts cranking over. Never messed with anything newer than a 97

[BR3W CITY]

That is probably the broadest question you could ask.
Have you had the ECM setup for the swap? Even in stock-for-stock swaps, VATS can cause problems. Is it throwing any codes?
Probably worth doing a CASE relearn for the crank.

Are you saying that when you turn the key to the first position (on) it starts trying to crank as if it was turned all the way to the second position (start/run)? If so, then the wiring is wrong, or something is physically wrong with the ign switch.