How do you fix a 2007 avalanche tailgate that won't lock?

To fix a 2007 Avalanche tailgate that won't lock, first check the tailgate latch mechanism and ensure it’s clean and free of debris. Inspect the locking cable for any damage or disconnection; if it’s loose, reattach or replace it as needed. Additionally, examine the lock cylinder and ensure it’s functioning properly; lubricating it may help if it’s sticking. If these steps don’t resolve the issue, consider consulting a mechanic or replacing the locking mechanism.