Quiet sound from under the dash

1299 Views 14 Replies 6 Participants Last post by pszemol, Jul 10, 2017

pszemol

Discussion Starter · Jul 4, 2017

When I make my Passat really quiet by not turning the engine on and switching off the Climatronics I still hear something buzzing, crackling - the sound is coming from under the dash, where passenger normally keeps their legs.

It is quiet enough I do not hear it while driving, but I am curious what can it be?

The sound resembles slightly the actuators of the vent flaps, but why would the sound be there all the time, even if blower is off and A/C is off?

I have suspected the intake air fan inside the Climatronics module but I disassembled it, removed this fan, clean the dust of it with a soft brush and from the thermistor but it did not help, the sound is still coming deep from behind center column.

Can anybody guess what it might be?

Pszemol
--
2004 Passat GLX, V6 2.8l

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Tomvw

· #2 · Jul 6, 2017

Maybe the after-run coolant pump, you could try unplugging it.
Does it only happen after the engine has been running ?
How long does the noise go for, is it more than 2 minutes ?

pszemol

Discussion Starter · #3 · Jul 6, 2017

Tomvw said:
Maybe the after-run coolant pump, you could try unplugging it.
Does it only happen after the engine has been running ?
How long does the noise go for, is it more than 2 minutes ?

What is coolant pump?

Do you mean water pump?

The sound starts when I turn the key in the ignition to ON and seems to continue forever.

Pszemol
--
2004 Passat GLX, V6 2.8l

Tomvw

· #4 · Jul 6, 2017

I read that wrong, I thought you meant after the engine was switched off.
The after-run coolant pump is a small electric pump near the alternator that circulates coolant for about 2 minutes after the engine is switched off.

You can't switch the Climatronic off, it is always on with the ignition and has a small fan to circulate air over the interior temp sensor.
I expect that is what you are hearing.

pszemol

Discussion Starter · #5 · Jul 6, 2017

Tomvw said:
I read that wrong, I thought you meant after the engine was switched off.
The after-run coolant pump is a small electric pump near the alternator that circulates coolant for about 2 minutes after the engine is switched off.

You can't switch the Climatronic off, it is always on with the ignition and has a small fan to circulate air over the interior temp sensor.
I expect that is what you are hearing.

Thanks - did not know there is a 2nd pump like this... All cars have it or just VW?

About Climatronics - when I keep pressing the blower speed down, eventually all activity stops and display shows OFF. Are you saying this is not really off?

I wrote in my op about this little fan- it is not that, sound comes from deeper under dash - behind center column, more on the passenger side.

Pszemol
--
2004 Passat GLX, V6 2.8l

Passat2.8

· #6 · Jul 7, 2017

Try this: make the car as silent as possible, hear the noise, then switch your power mirror switch to the drivers side. If this doesn't point something out, I'll explain.

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pszemol

Discussion Starter · #7 · Jul 7, 2017

Passat2.8 said:
Try this: make the car as silent as possible, hear the noise, then switch your power mirror switch to the drivers side. If this doesn't point something out, I'll explain.

2nd Mate Unlimited
MSC

I am away from the car til Sunday...
What is your idea about? Tell me more, pls!

Pszemol
--
2004 Passat GLX, V6 2.8l

Passat2.8

· #8 · Jul 7, 2017

pszemol said:
I am away from the car til Sunday...
What is your idea about? Tell me more, pls!

Pszemol
--
2004 Passat GLX, V6 2.8l

If you sit in the car with everything off, you can hear a very faint buzzing from the side of the car you have the mirror switch selected to-at least in mine. Something to do with the power mirrors of course.

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jimbo7

· #9 · Jul 7, 2017

So is something not working right? I'm lost.

Passat2.8

· #10 · Jul 7, 2017

jimbo7 said:
So is something not working right? I'm lost.

It's normal, nothing wrong.

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Iowegian

· #11 · Jul 7, 2017

That doesn't seem normal to me. There should be 0 current running through the mirror adjustment motor if the joy-stick part of the switch isn't touched. Buzzing implies a small amount of current flowing through the motor and probably a bad mirror switch.

Passat2.8

· #12 · Jul 7, 2017

It's done it since the day she's been in my possession, including the new mirror switch. Never a problem, but it always stops shortly after the interior lights dim off.

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Iowegian

· #13 · Jul 7, 2017

Interesting....I'll have to check mine. But my hearing is so bad I'm not sure I'm qualified

jjpark

· #14 · Jul 8, 2017

Passat2.8 My mirrors made the same noise after shutting the car off on my 01 V6 GLX. Noise stopped after interior lights went off. Never got to the bottom of it before selling it but my 04 V6 GLX does not make any noise from the mirrors.

If it's coming from behind the dash it could very well be something from the AC. Maybe a flap motor?

pszemol

Discussion Starter · #15 · Jul 10, 2017

Passat2.8 said:
It's normal, nothing wrong.

2nd Mate Unlimited
MSC

I will check it after work.

Is there a dedicated fuse in the fuse box just for power mirrors? I could take it out to confirm the sound gone.

Pszemol
--
2004 Passat GLX, V6 2.8l

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