I have several different issues first is this past Saturday I was at my father in laws and my Tahoe just locked itself I left the keys in the floor and as we were walking inside it just locked all the doors.
my second issue is on the driver information in the dash and it will randomly change the language.
my third issue is I was having a problem with the shifter going into park and then I heard a loud click and then did not have any issues anymore and was looking under the dash and found this part plugged in just hanging down it connects to the shifter rod and a metal bracket. i have searched and searched but could not find this part anywhere does anyone what it is called?
any help would be great.

 

That is the brake/shift lock,you don't have to apply brake now to get out of park?

 

i have not tried to take it out of park without the brakes

 

Genuine GM 26094827 Automatic Transmission Shift Brake Interlock

 

Phantom door locker. When you were getting out of the Tahoe you probably bumped the door lock switch on the arm rest, this signals the computer to lock the doors automatically about 10 seconds after you're walking away, just as you remember that you left the keys inside. (Don't ask how I know this)

 

that thought had crossed my mind but this was not the first time it happened. it happened to my wife but luckily she had the keys

 

Doesn't your key in ignition buzzer work when the door is open? If you removed the key before you got out and laid it down, I found my experience that it's best to lay in your lap so when you get out, it will fall on the ground at worst. Don't ask me how I know.