Rear wiper motor will not run and the rear liftgate as well as the passenger rear door will not unlock in a 2008 chevy Tahoe Hybrid

 

here is very low probability it's actually the wiper motor burnt out.

The liftglass actuator, liftglass button, and rear wiper motor are wired in series with like three safety shutoffs. If your glass is open or thinks it's open, no wiper. if your liftglass button is shorted, no wiper. There's also a possibility the wiring harness became damaged between the gate and the body where it runs into the space above your headliner.

Haven't had the privilege of the whole gate being non-functional. I'd bet it's the same electrical ball of wax.

Make sure the button on the headliner isn't turned off, check fuse, tear stuff apart in the back, test for power, you'll get it.

 

There is a pad on my rear liftgate that either unlatches or starts the automatic liftgate when you squeeze it. Its on the inside of the handle. This can go bad, and maybe it will solve some of your issues. When I looked at my truck, used, I went to open the gate. Couldn't open it with the remote or the handle. I "think" I could by pressing the button in the headliner, but that was it. They had to order the part, but by the time I picked the truck up, it was replaced and all was working again.