maximln

I just took delivery of my new 21 Yukon XL AT4 and everything works great except fot the liftgate. You can push the button on the exterior of the liftgate to open it and it opens fine but if you try to open it any other way you hear 2 beeps and all the lamps flash twice, like something is prohibiting it from opening. Using the remote, the interior button on the overhead console (yes, it is not in the "OFF" position) the "Close" button on the liftgate or even "kicking" the GMC logo light, I always get the 2 beeps and the lamps flashing twice. I ended up taking it back to the dealer and they are stumped too. From what the technician is telling me, the literature that GM has for the tailgate is incorrect and basically useless to aid in diagnosing the problem. Has anyone had this issue? Thank you, Max