while your at the RKE project,,, i thought of something while searching for my car in the airport parting lot. Yep,, it was hard to remember where exactly i parked in the dark.
Hitting the door lock button, perhaps the relay could also momentary make power contact to cause the headlights to flash as well as a short audible horn burst. It would only last as long as the relay contacts make/break
Thats how the stock system works actually. My mountaineer does just that when I press the door lock button twice. Once locks, the second press kind of arms the system.. even though there isn't much of an alarm.