I as you tried for a hour to get to work. Called Chevorlet and they got me going. I also have the newer version of the home link system. The trangle one. You have to hold the door transmitter up to the buttons in the Tahoe and hold both buttons together for it to work.
Customer service for Chevy gave me the phone # for the instructions.
The new system uses the three LEDs, not the triangle...the triangle is the OLD system. Mine won't work without getting the additional equipment from Lear, so I just use the regular transmitter...