This is a very good YouTube video of a Jeep Liberty that won't start with ignition switch/key and the full diagnosis process to find the problem.
Then he walks you through in detail how to replace the bad ignition switch / actuator mechanism which had broke off preventing it from starting.
It's a gasser, but the process and basics are the exact same for the diesel models.
enjoy.
https://www.youtube.com/watch?v=PwbEmSCX8kM
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Supporting Vendor and Moderator of LOST05 Jeep Liberty CRD Limited 
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