AGHH!! I fell for this. Test drove '23s but wound up buying a 324 FLASH and thought it MUST have the garage buttons so never really checked and didn't realize until singed sealed and delivered siting in my driveway ready to program them and WHOOPS, not there!
This sounds promising.
What about - any shortcuts to the horn lead wires where you could tap in and grab the signal to hook up to a relay for a 2nd horn?
I have a electric "air horn" I want to add.... :)
I tried this for a long time and finally his note of “big side down” and “all in less than 30sec” worked magic.
Again,
KEY BIG SIDE DOWN
ALL DONE IN LESS THAN 30sec.