Hello,
The lift gate on my 2016 Tahoe is stuck open and have tried everything and I can’t get it to close. The dealership is already closed for the evening and we are getting rain and snow tonight and tomorrow. Any ideas welcome!!!

 

My guess:
Since your 2016 likely has push-button electrical opening, you'll need to try to remove the connector for the 3rd "arm" that actually raises and lowers the left gate. The pair of lift cartridges should hold up the lift gate so you can lower manually.

If manual open and close, support the lift gate about an inch higher than what it is now, like with a 2x4. Remove the two lift struts and then remove the 2x4 and lower the lift gate manually.

I'm going by what my 2014 has....

 

I'm a bit confused - I can still easily close my tailgate manually without the power assist. Are you saying the power-assist mechanism is physically jammed, preventing closure?

 

ALL we know is what CTtahoe343 posted. We can guess he's in Connecticut, maybe not....

 

Some owners do not know that they can manually close the tailgate.

 

Some owners never open the owner's manual. You think Mrs. Cusser has????

 

Sometimes disconnecting the negative cable from the battery for 15 minutes to re-set the vehicle computer can get weird stuff working again.

 

THIS. This has absolutely worked for me with this same issue.