i replaced the steering column and now the truck wont start

You can give this a try. Have the battery fully charged! Turn ignition on leave in the on {Do not atempt to turn on the car just to the run position} position for 10 min the theft light will turn off. Cycle the key off then on and leave in the on position for 10 more min. Repeat. turn the key to the off position and try to turn on the car. Should work its the reprogramming procedure for most GMs without a scan tool. Good luck.

Unless you use the key that was used with the other lock cyl. It is not going to start. That key has an encoder chip in it. May be able to change the lock if it is ok.