tailgate 2015 Tailgate lock won't turn all the way to unlock, binds.

[Outdoors_Guy_88]

I have a 2015 Sierra "Work truck" with manual tailgate key lock (no remote electronic opening or camera; plain latch).  The lock has worked great up until now.  (Normally, turning the key 1/4 turn to the left unlocks the tailgate by engaging the latch handle.)

 

Now, I can turn the key just short of the unlock position (turns freely, like usual, not gritty or rusty or sticky), but then the lock binds.  Feels like something internally fell into the mechanism is preventing the lock cylinder from turning the last little bit.  Therefore, my latch handle will not engage to open the tailgate.

 

Is this a known/common problem?  Fixes?

 

[CrawlSlow]

Take it apart, takes about 10 min, inspect everything. My guess is that there's broken tab inside preventing your handle from working correctly.