Soft Intermittent Buzzing Sound When Heater Enabled

[GMan]

I can reproduce this observation with 100% consistency, and so I'm not sure if this is simply expected behavior or not.

At stand-still, for example in Park, when I turn on the heater from Off to even fan level #1, I will hear a buzzing sound for 10 seconds or so, followed by silence, followed by the 10 seconds of buzzing again, followed by silence, and this will repeat until I turn off the fan. It is entirely likely that with music on or driving, this buzzing sound would not be noticeable but at a stand-still when quiet in the car, it is.

Please note, I'm not talking about an air blowing sound / airflow. It's a buzzing sound.

Is this just normal?

Please vote at the top of this post and all comments welcome as well.

 

[OCDC]

I have this too. The sound is loudest coming from the front center vents. I had service look into it a couple of months ago. The service advisor did a poll of the cars that were in at the time and he found that 4 of the 10 he checked had it. Not quite a majority, but a strong plurality. Because of the number, he said it was “normal”. I personally want one of the 6 that didn’t have it. It’s a really annoying tone. I wrote about it a while back.

As best as I can tell, it’s coming from a pump for the HVAC or its drive electronics. The noise goes away when you turn off the HVAC via the power icon.

 

[CLTGT]

I also get a bit of a "gurgling" or fluid/bubble sound as if fluid with air bubbles was moving through some tubing somewhere under the center console. I brought it up to the mobile tech a couple weeks ago and he said it was "normal" and probably a result of the heater operation. This is totally different from your issue described above, but somewhat related. I just turn the stereo up and ignore it.

 

[DeaneG]

I have it in my car. Sounds like the buzzing of an HVAC motor or actuator winding that is being driven by a pulse-width-modulated current at an audible frequency. But it's quiet enough that I only notice it when the car is stopped and music off.

 

[elusive7]

I have it in my car. Sounds like the buzzing of an HVAC motor or actuator winding that is being driven by a pulse-width-modulated current at an audible frequency. But it's quiet enough that I only notice it when the car is stopped and music off.

Yup exactly this as well. Was told by service that it's "within spec" unfortunately. Looks like we'll just have to crank the music up a bit!

Additionally, I seem to be experiencing some sort of buzzing from the air vents lately that is unrelated to the heater being on.. it sounds like a rattling? From the front air vents above the pilot panel. Difficult to pinpoint exactly where it's coming from.

 

[OCDC]

A brief update about this heater buzzing noise. I’ve since learned that the heating element is a resistive type connected to the HV system through a PWM driver. This kind of design can have a mechanical response to electric current pulses that creates a vibration in the heating element, similar to how a toaster oven can buzz when it starts up. It is what it is today; not broken or wrong, just a compromise. Maybe Lucid can address this with a firmware update in the future by adding some randomness to the PWM frequencies or something.