GMC Troubleshooting Questions? Ask a Mechanic for Answers
This is with the cover removed
So the door handle came off on the outside? The rod is probably jammed down not allowing the lock to release. Can you get youe hand in th door on the latch? if so feel where the rod hooks on and open that clip to release the rod from latch.
There is no text book way to tell you how to fix this. I would try moving the latch where the rod should go on and see if it allows door lock to release. Otherwise the latch will need to be broken apart. This may involve removing window so you can get a long screwdriver down to it and break it apart.