New to forum

Acquired my sons 2007 dodge ram 1500, 4.7 v8. 4x4 He passed about 3 weeks ago at 18 years old. Truck didn’t have a key so I bought and replaced the lock cylinder. It does fire up briefly but then dies. What is the purpose of the control module receiver that wraps around the ignition and plugs into the ignition switch?
Author: NewToMopar