Regarding your tail and brake lights, they use a 1157 bulb, which is dual power. When the ignition is ON or in PARK, they turn onto low wattage. When either brake switch is depressed, the high wattage part kicks in, giving you full light. However, with enough corrosion, the ground connectors on the sockets can fail, so the blue wire (running lights) grounds to yellow (brake light), making it seem like the brake lights won't come on. Happened on my bike, a buddy's 550, and another 750. To troubleshoot, disconnect the brake switches. The light should stay on, but on low power. If they get brighter when the switches are connected, the switch is sending an on message. Adjust it, or replace it.