I have a 99 Silverado with a 5.3 V8, automatic transmission which had an ignition switch failure. The interface between the key switch and the ignition module crank was worn out. So, I pulled it apart and ordered the new parts.

I want to use the truck while I wait on the parts but when I manually turn the crank in the ignition module, it cranks but shuts down immediately. Can anyone advise me how to correct the problem?

 

I don't know what you mean by "how to correct the problem" since that how it's supposed to work. When you turn the lock cylinder with the key, the Passlock sensor sends a voltage signal to the BCM. You probably separated the lock cylinder from the ignition switch and disconnected the electrical connector with three tiny wires from the Passlock sensor. If you don't care about theft deterrence, it isn't too hard to bypass the Passlock system. Just do a web search for "Passlock bypass" or something.