1. Check for Obvious Issues:
* Is the latch mechanism simply jammed? Try gently working the handle and latch from both the inside and outside. Use penetrating lubricant (like WD-40 or PB Blaster) on any moving parts. Sometimes a simple obstruction is all that's preventing it from opening.
* Is the key working? If the tailgate locks, ensure you are using the correct key and that it's properly inserted and turning.
2. Access from Inside (If Possible):
* Interior Release: Some Avalanche models have an interior release mechanism for the tailgate. Check the inside of the cab, near the rear, for a lever, button, or switch.
3. External Access (If the Interior Release Fails):
* Drill the Lock: This is a last resort. You'll need a drill and a drill bit slightly smaller than the lock cylinder. Carefully drill out the lock cylinder. This will damage the lock mechanism, requiring replacement. Be extremely careful not to damage the surrounding metal.
* Break the Latch (Very Destructive): This involves physically breaking the latch mechanism, likely requiring tools like a hammer and chisel or a bolt cutter. This is a very destructive method and will necessitate a replacement tailgate latch.
* Remove the Tailgate Panel (Advanced): This is for individuals with mechanical experience. You'll have to remove interior panels and potentially exterior panels on the tailgate to gain access to the locking mechanism. This approach requires significant automotive knowledge and the right tools.
Before You Do Anything Destructive:
* Consult a Repair Manual: A repair manual specific to your 2005 Chevy Avalanche will provide diagrams and instructions for accessing the tailgate latch.
* Professional Help: If you're not comfortable attempting any of these methods, contact a locksmith or an auto body repair shop. They have the tools and expertise to open the tailgate without causing further damage.
Important Note: The specific method depends on the nature of the breakage. A broken handle is different from a jammed latch. A picture or more detailed description of the problem would help determine the best approach. Always prioritize safety and minimize damage when attempting any repair.
