Thanks Marc - I've been thinking of putting dual intensity red LED strips on the back of my side boxes. One of the wires on theses strips is for braking. On most bikes you'd just tie it into the brake light wire. The problem with late BMW bikes is the computer control of the electrical system. If the tail light burns out, the brake light takes its place automatically. I don't want to mess this feature (tie directly into the brake wire).
I'm thinking that if the moto engineers at BMW are really on it, they would have put an auxiliary contact for brake lights on an electrical bus somewhere.
Does it exist? (or is there as much thought given to this as to control ergonomics?)
Not that I'm aware of. What does exist on some bikes, and I don't know which have it and which don't, is a system where both filaments are run at a reduced voltage for tail light function and at full voltage for brake light function. That kind of messes up generic dual intensity LED strips.
The lights in the link I mentioned handle this and include strips that most mount upon either side their license plate.
Have the P3's on my GS. The P3's run at a reduce level so they operate as a taillight and they actually waver or pulse a bit when viewed from the side. Web site says they do this so they stand out more when viewed at an angle, when viewed from straight on, they are steady. When you hit the brakes, they are very bright. Some mount them on both sides of their license plates, I made my own mounting plate and put them across the bottom of my plate, when placed end to end, that is about how big they are. This way I have two taillights that are easy to see and two big brake lights. And yes, my 07 GS burns both filaments in the taillight all the time at a reduced level that brightens when brakes come on.
I love my P3's, had a few of the LEDS go out in one bar. Contacted P3 about it and had a replacement in about two days. Only thing they asked was to have the bad one mailed back to them so they could see what went wrong. Mailed it back in the pre-paid envelope they sent. Great customer service.
Okay, thanks for your response. I guess the only way to set up auxiliary brake light would be to tack on an auxiliary electrical system and switches. Maybe a button by the grip to activate brighter "back-off" lights would do the trick. The left hand doesn't have enough to do on this bike, anyway.
Parts dude at my local beemer dealer told me tapping a relay to the brake light wire would not draw enough current to mess with the brain. Seems the brain senses voltage differences that a relay would not significantly change. So, rather than tapping the LED strip to the brake light, it can come from the battery like everything else, switched by a relay.