-
The K7 always uses red and black for powering the device. The yellow is simply seen by the K7 as just a signal the bike is running. No power on the yellow is used to operate. When you turn off the bike, the yellow wire goes dead so the K7 knows it is in parked mode. It then continues to use power on the red and black for the G sensor and when cameras are turned on by a jolt. If the voltage falls below a certain voltage it turns off totally. I believe it cuts all power when voltage drops to 12.5.
I hope this helps.