Squeaking from cabin heater, dependent on power output

[ChadFeldheimer]

I have a high pitched squeaking, almost like a chirp. It is not constant - it's like a bird chirping away. From the driver's seat, it sounds like it's coming from the the right front of the car.

Car is a P85D.

I've tried recording the sound but my phone doesn't pick up the high frequency noise.

It has happened intermittently over the years, but is now more frequent. Frequent enough that I've been able to discover more about the problem.

1) Never occurs with HVAC off
2) Never occurs with HVAC trying to cool the cabin
3) Occurs when HVAC is trying (I think) to heat the cabin, but resistive heating is off
4) Never occurs when resistive heating is on
5) When the above conditions are right, it reliably reproduces when power consumption is around 50kW
6) Rarely occurs when power consumption is low or above 100kW
7) Sound does reproduce while supercharging... interestingly, while charging at around 50kW.

Unfortunately, highway cruising often consumes enough power that the car chirps away. It was pretty annoying on a recent day trip.

I've scheduled a service appointment (car is under warranty) but there's a decent chance weather conditions won't be conducive to reproducing.

Has anyone encountered something similar?

Thank you!!!

 

[The Lorax]

Did you ever find out what was causing the noise? I now have a similar noise and wonder if I should take it in for service.

 

[ChadFeldheimer]

Yes, eventually it got so bad that it was happening almost all the time. It was the HVAC blower motor.

Good luck!