The Turn Signal audio “alarm”,
if I’m comprehending this properly, is a reminder beep that is in-sync with the turn signal and hazard warning flashing lights, that kicks in after a certain amount of time has passed, [thank you Sergey (ssh16) for clearing this up for me] is apparently not really an alarm, but audible clicking noises replicating the sound of turn signal flashers of yesteryear, in-sync with the turn signal and hazard warning flashing lights, and doesn’t seem to be loud enough for a majority of us driving 124 Spiders, especially with the top down, which is how the car is meant to be driven. I’m writing this article in answer to seeing another inquiry posted on the Miata.net forum by MX-5 owners, also wanting the volume turned up. Even at the Loud setting, just like the beeps letting you know you’ve reached the lower and upper limits of the cluster dimmer control (rather than mechanical stops), I know I can’t hear them either. Yet, I almost jump out of my seat when a faulty interpretation of ABS data triggers false TPMS alarms, proving to us – that same audio transducer, located on the rear side of the instrument cluster circuit board, is capable of being plenty LOUD!
Sergey provided a nice photo of the actual transducer (think of it as a tweeter) in his excellent Instrument Cluster analysis discussion. I’m assuming it’s obscuring the “BZ1” component callout (Buzzer #1), and I’m also curious what purpose a second transducer (BZ2, which is not present) was intended to serve (text-to-speech?).
Anyways, BZ1 is mounted adjacent to the stepper motor for the speedometer, close to the right-side edge of the circuit board, and this probably aligns quite nicely with the small slotted grill opening in the cluster canopy designed to allow some portion of the emitted sounds to enter the cabin.
So figuring out how to alter the existing personalization command that communicates to the Body Control Module (BCM) via the HS-CAN network, the volume level value for the loud setting for the Turn Signal audio (which appears to use the same transducer) to a value much higher than the current setting, yet not quite as loud as the TPMS alarm, would be of value to those of us, currently unable to hear the alarm. The TPMS Reset acknowledgement beep (which is quieter than the alarm) volume seems about perfect, and I would like to determine that value, and use it as a good starting point. If someone could intercept these commands over the HS-CAN network, a tweak that would replicate the personalization command (using the louder volume value though) should be easy enough to write. This is all assuming that the values aren’t predefined in the BCM, and that the command isn’t simply choosing either the Low or High predefined values, but rather, is actually defining the preferred volume value.
I’d like to familiarize everyone with the personalization setting shown directly underneath the Turn Signal audio volume – the Lane Change Three-Flash feature. I find that enabling that feature to be very helpful, as it means that by using the momentary-on portion of the switch, resulting in three light cycles, rather than one, and thereby not actually engaging the turn signal lever past the “click” into it’s auto-cancelling mode, it can’t be left on accidentally. By using this feature for shallow turns, you should find your turn signals behaving as you’d expect, since the self-cancelling feature functions properly after sharper turns.
Here is an illustration showing how the Turn Signal audio “alarm” functions, and by comparing it to the top illustration, you can see that both alarms seem to be actuating the same transducer (labelled buzzer):
I was hoping that perhaps a Mazda or Fiat dealer could program the volume, but found this in the Miata forum, which implies that they can only select low or high, just like we can from the CMU Settings screen, but not the actual volume 😦