My car has developed a weird humming noise from behind the dash, and it's linked to the temperature settings.

If i set the dials to cold then I can hear the humming noise at one pitch.
If I set the dials to hot, the noise changes to a slightly higher note.
If you set the dials anywhere in between the noise goes from one to the other at about 1 second intervals. almost like a (very) quiet siren.

It's too quiet to catch on video, but it's getting very annoying.

Now I don't know much about the heating system on these, but my guess is that there is some sort of flap or mixer valve that is stuck/sticking, and the noise is the motor trying to move it to different positions, hence the different noises when I change the required temperature.


It's hard to locate where it's coming from, but I'd guess it's somewhere central on the dash about knee height.


Not that it probably makes any difference, but it's a 2010 5.0 S/C AB.

Anyone experienced this before, or got any pointers?

Thanks

Jon

Jon

Have a search for heater stepper motor, heater fan noise, FSR (final stage reistor) and/or engine ecu fan.

Seems quite a bit of info around odd noises, may be of help. Cheers
Richard

(there are no such things as an ordinary FullFat, an ordinary cat or too many tools)
2011 TDV8 Vogue Santorini Black
Gap IIDBT

Thanks for that.

From reading what I can, it sounds most likely to be a heater stepper motor.

When I get a chance I'll take one of the centre console side panels off and see if I can find it.

Cheers Jon

you're welcome.

If you have time, a few pics and words would be great Jon.

(so when it happens to me I'll have a great reference ) Cheers
Richard

(there are no such things as an ordinary FullFat, an ordinary cat or too many tools)
2011 TDV8 Vogue Santorini Black
Gap IIDBT