3500 disel injectors not opening after changing ignition switch

Doe,s your truck have transponder chip in key?

You may have to have your new key,s programmed to your computer in your truck,until the you will get fire but know fuel

You don't get fire in diesels. Have the keys programed to the truck. If you have an owner's Manuel, it will tell you how. If not, call or drive to a GMC or Chevy truck dealer and ask them how to program the keys. Most sales people know how to do that also. If that does not work, make sure all the wires are correct and or connected. Is it the injectors or glow plugs not getting any signal? Perhaps when the keys are programed, everything will function correctly. While at the dealer, they are the ones that have an expert on changing ignition switches. I have always found these people are a bit reluctant, but really willing to help. They know if they pi-- you off, you will not come back.