Pretty annoying not to have homelink the the daily driver. It'* in everything else, even though they didn't come with it. I happen to have a few Homelink'* laying around. Tested this one up and it worked great on the bench. Headed out to the Regal. Using GM'* manual to remove the visors was unsuccessful. All this meant was that I'd improvise a bit more.
Pulled the visor center clips down and inspected the wiring of the mirror for a battery voltage and ground.
Successfully tested the Homelink by pushing the wires into the mirror connector. Homelink didn't stay in the connector for the pic.
Stripped back the orange (12+ battery) and black (ground) then twisted the wires of the Homelink to the wiring harness of the mirror.
Always solder and tape connections, then there won't be an issue. Heatshrink whenever possible.
Grew a huge set, reached up and cut/pulled the backing of the headliner out of a section big enough for the Homelink.
Grew an even bigger set and cut into the headliner where I believed the buttons should go. Doing all this w/o measuing or any reference point was a bit risky.
Clipped the buttons and face place back onto the module, only to find out I put the Homelink in the same place GM puts the sunroof button on a Regal....slightly closer to the driver.
Retested with success
Total time was 30 minutes.