I originally posted this on another forum but neglected to include it here, sorry about that. It's here now though.
Like many others, I also had seemingly unresolvable issues getting my Homelink control programmed until a very friendly lady with Genie helped me solve the problem.
*2014 Z51 Stingray with Homelink on sun visor
*Genie PowerMax 1200 garage door opener with Homelink support
I followed the instructions provided on the Homelink website with no success because the sun visor button would never flash rapidly. I also called their support number but could not actually speak to anyone because the only support available for vehicles built after 2003 is a computerized step-by-step walk through which has no way to actually solve a programming problem. I thought this was extremely poor on their part. I attempted programming with & without putting the remote into Intellicode 1 mode with no success either way.
After a few days of frustration I decided to give Genie a call with little hope of success because Homelink is not actually a Genie service. I was able to speak to an actual person , a very friendly and helpful young lady who said she would help me even though Homelink is not actually their service or product. After going through the same steps I did for the previous days without any success again; she asked me to pull the clip off the back of the Genie remote I was using in an attempt to program the sun visor button with and give her the numbers stamped onto it under the spot where the clip goes. After giving these to her she said; "Aw, there's the problem". The last numbers on my Genie are "2.0.3". She then told me she was going to send me a different remote to use in programming the Homelink in my C7 because the original Genie remote roles the Intellicode codes so fast that the sun visor button could not catch it.
So after a few days I got the promised remote (At no charge) and was able to program the sun visor Homelink on the first attempt!
The model number of the remote she sent me is "GITR-3".