Here's the latest...for the Horn Relay and Key Buzzer PN 3579205, disconnect the key in buzzer wire (post D) from the relay, connect it to the new chime black and blue wires (if you are going to use the Radio Shack one I purchased. Then tie the red wire from the chime and attach it to the violet w/ tracer wire (post C) and listen to a much better alternative to the buzzer. Nice soft much less annoying two tone electronic door bell chime.