How to disable the child lock on a 20070 Tahoe

That's not the child lock. You have a problem with the locking mechanism itself / probably the actuator.

My guess would be contacting the dealer, or website.
now I'm not completely sure but I hope this helps??

open rear doors and flip lever to off

Look on the door, when it's open, select. LEHenson.com

If they won't open from the inside but will from outside check the child lock slide switch on the edge of the door while open.

as child lock electronically disables rear doors central locking will not work

child safety feature made into the system.. dont know if the timer can be disabled or not...why do this anyway? must ask...

When you open the door, on the back edge of the door there should be a switch that you can move to disable/activate the child proof locks.

there is a slider switch on the door(between door and frame) that you can lock or unlock the child locks to prevent them from opening the door from inside but still can open door from outside----just slide the lock switch to enable or disable the child lock.

if they are stuck/stiff---you may have to remove the door panel for repair.

Usually they work free with a liitle lubricant(WD-40) to slide easier.

kind of hard but it can be done but what probly happen is that the child lock is hafe and hafe not ingaged or disangeged so it's stuck