Key buzzer to chime

Purchased the chime from Radio Shack today ($12); doesn't sound too awful (better than the factory buzzer) very mild door bell sound. Unhooked the "key in" buzzer terminal but haven't been able to pursue the the remaining 3 wires at the horn relay to find the power, due to other commitments this afternoon (grand children came over). I'm confident this will work instead of the buzzer. I'll let you know.