JGiardino89

2005 A8L 4.2 with 2 zone HVAC.


The rear pillar vents are not putting out heat even with the HVAC set to HI on just the vents. Also, the vent to the left of the MMI screen will only put out "warmish" air. I have adjusted the center vent to be warmer, and it didn't help.

I haven't had anyone do a VCDS scan yet, but was just looking to see if anyone has had this issue before and resolved it.

(Yes I know I need to get the VCDS program...)


TIA,
Joe

97urS6

Hey Joe, I was wondering the same thing, I have never noticed any air flow from those vents either.... So I thought I would try to find out if there was some special combination in the HVAC controls that got air to flow through those vents.

So I cranked the blower up to max and tried the manual setting for the foot vents, then dash vents then defroster vents. What I found was that you need to have the controls set to the dash vents to get any air out of them.

And not only that it is somewhat less Force then up front. Not only that, it was s fair bit cooler as well... but my car was quite cold, so, I'm sure that would improve once it was warmed up.

So my guess is that with your HVAC setting on Auto, the blower would be quite low, and generally distributed between all vents... and thus the amount of air reaching those vents would be quite little... maybe unnoticeable?

The other thing that I found, was that I had to close both of the front center dash vents rotary ***** to get air to stop from both of the vents on either side of the MMI Screen! Just closing the **** on the passenger side only slowed the air flow, not until I closed the one on the driver side did Air completely stop on both! An interesting and unexpected find!

JGiardino89

Maybe I should have worded things a little differently. I am getting air flow from the vents, but the air is cool when I have the HVAC on HI.

jlbell

Sounds like you might have to adjust the vent temperature in the "setup" menu for the climatronic system. Please see this document for more information: https://www.dropbox.com/s/kw25vf0wpj...irCon.pdf?dl=0

JGiardino89

I have already adjusted the center air vent to be warmer

97urS6

Any luck in figuring this out? After reading the doc from the link provided, I see that the A8 uses an electric heater near the end of heating ducts that feed the rear seats... maybe those are not working?

JGiardino89

The electric heaters seem to only be used by the vents under the seats IIRC.

I'm hopefully having the car scanned today to see if there are any HVAC malfunctions. I wonder how much those electric heaters are to replace if they are faulty.

MP4.2+6.0

Last I looked, pricy. In $400 range, each. Yes, only in those two floor vent areas.

JGiardino89

Didn't someone try to repair them but failed because they are bonded to the plastic?

JGiardino89

No fault codes in the HVAC system after a scan with VCDS.