Cabin Heater Noise

reilljp

Well-known member
Joined
Mar 9, 2016
Location
San Carlos, CA
TDI
2015 Passat
When the cabin heat is turned on, I hear a humming sound that comes and goes. It is not loud but has become quite noticeable to me.

If the dial is at full cold, there is no noise. If any heat is added, after about 10 minutes the intermittent humming starts. It will hum for 10 seconds or so, stop for the same, and start again. The duration is not predictable, it just comes and goes.

The noise appears to come from under the steering wheel near the door, but that could just be where the noise is being reflected.

Any ideas what this could be?



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740GLE

Top Post Dawg
Joined
Aug 19, 2009
Location
NH
TDI
2015 Passat SEL, 2017 Alltrack SE; BB 2010 Sedan Man; 2012 Passat,
its summer, why you running heat?

You got AC on? You maybe hearing the compressor duty cycle when it's not trying to run full cold?
 

reilljp

Well-known member
Joined
Mar 9, 2016
Location
San Carlos, CA
TDI
2015 Passat
Not full heat, just a little heat in the morning.

I don’t hear the AC when the temp is set to cold. I always run the AC, regardless of the temp setting.

The noise is coming from inside the car.


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740GLE

Top Post Dawg
Joined
Aug 19, 2009
Location
NH
TDI
2015 Passat SEL, 2017 Alltrack SE; BB 2010 Sedan Man; 2012 Passat,
Right so if it was full cold, the ac will be at max duty cycle, but if you "add heat" that duty cycle is now what 50% or something? Shut the ac off and try "adding heat" see if it is the same.

Other than that, not sure.
 

reilljp

Well-known member
Joined
Mar 9, 2016
Location
San Carlos, CA
TDI
2015 Passat
You are right, I turned off the AC and the noise stopped. There must be something wrong with the AC then. Why else would I hear a humming sound coming from inside the car? It’s not a AC type sound.


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740GLE

Top Post Dawg
Joined
Aug 19, 2009
Location
NH
TDI
2015 Passat SEL, 2017 Alltrack SE; BB 2010 Sedan Man; 2012 Passat,
Progress!!! Maybe a sympathetic vibration?

Pop the hood see if you can pin point the sound with your ears.
 
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