My rear window lock is not functioning at all, to open it I must crawl back there and use a screwdriver to open the window just to get the tailgate open!
Why Chevy designed it this way is beyond me as if the electrical fails there is no mechanical backup by using the key! Anyways are there any ideas to troubleshoot the situation?

 

I just developed a problem with my 2 door rear glass not opening. I hear the solenoid, but nothing happens. Noodled around on Youtube and found the plastic rod on the solenoid breaks.

 

You will have to disassemble the tailgate and reconnect the junction where the solenoid actuator moves the opening mechanism. This can be accomplished numerous ways. There is a replacement piece on eBay, or you can rig it back together with some stiff wire such as a coat hanger, depending on which part in there is actually broken and exactly how it broke. Good luck.