If you're curious, based on earlier feedback in the thread, we researched the use of an audio device instead of an LED to signal diagnostic and mode data. The suggestion was that audio feedback would eliminate the need to poke one's head under the dash. I like this idea ( and kudos to Oakleaf for suggesting it ) because it could improve the customer experience and simplify manufacturing--we could have a single version of our PCB instead of two versions featuring either a left- or right-side mounted LED.
In finding a suitable audio component, the initial challenge was a tiny power budget, so we focused on piezo buzzers. Another challenge was the physical dimensions: we have very little open real estate. The good news is that although it was physically larger than the MCU/CPU that powers our system, we did find a piezo buzzer that fits our PCB.
You can see a picture of the piezo hand soldered directly on top of the MCU in this picture below. Our PCB is purple and the piezo is the large, slightly off kilter component in the center. Also in the picture are a few other piezo buzzers with which we also experimented.
The bad news is that none of the piezos generated enough dB to be useful in the broad array of vehicles and environments that we could reasonably expect them to be installed and used. This is an unintended byproduct of our housing: the floors and walls are 3MM thick in order to provide robustness and crush resistance. But this means that the piezo's buzzing is barely audible with even a modest amount of background noise--we had an office window open during testing and could barely hear the piezo.
So, for now, we have to stick with the light emitting diode. However, we replaced it with a 30% brighter part based on the thread feedback. (FYI, I sometimes use my iPhone with the camera on "selfie" mode to show me what's going on at the pedal if I want to skip climbing under the dash.)
I think that the ultimate solution is a wireless implementation that communicates with a mobile app. The challenge with that, again, is power budget. We've done some experimentation and as soon as the technology supports it, we will roll out a solution--but my guess is that will be several years from now, and probably many of you will have already purchased your next Leaf.
Thanks to everyone for the feedback to date. Best,