Last week my 2020 Suburban LT passenger rear door will not open from the inside but will open from the outside. Took panel off and cable seems fine.
Over the weekend, same thing happened to the drivers side rear door. Can't open from inside but can from the outside only.
Thoughts before I take it into a dealer?

 

did you look in your owner's manual?

 

Welcome to the forum.

If the child safety lock wasn't the problem and you take it to a dealer, I wouldn't tell them that you had the door panels off.

 

Had the same issue on wife's 2005 Yukon. Took off the door panel to investigate, then saw a sticker that looked like a spaceman, turned out that diagrammed a child with "helmet" over the head, and was the safety switch inside the door jamb. My grown-up daughter apparently accidentally kicked that switch over to lock. I had no idea...

 

😂
spaceman
It's not a helmet. It's a child in front of a symbol of a padlock

 

Ha !!! It IS a child in front of a padlock - guess my Phi Beta Kappa and Magna *** Laude in Chemistry didn't teach me that !!!! When I was a little kid, I learned 26 letters that could be arranged to form words, but sometimes these universal symbols just aren't so straightforward !!!

Just like Mrs. Cusser told me the "submarine light" was on once !!!

 

I've heard it called a "helicopter light" as well

 

Still waiting to see if this was the OP's problem, hope they report back.