05 1/2 ton chev sub liftgate won't open

[econn2000]

05 1/2 ton suburban liftgate will not unlock or open. All labeled fuses are good, lock/unlock relays work, all other doors work fine, even with fob. Is there a safety interlock? Any manual/emergency method of opening other than drilling?

[unplugged]

I don't have any particular experience with your model, but I have two thoughts:

If the window isn't rolled all the way up, it may have an interlock.

From the inside, remove panel screws/fastners to access the latch mechanism to open the tailgate so that you can get a closer look at what's malfunctioning.

Good luck, let us know what you find.