Heating only works on one side of the car?

[craig20102010]

Im having a problem trying to diagnose what could be causing only one side of the car to blow out hot air...

The drivers side will not blow out hot air. Luke warm at best. Compared to the passenger side it is freezing.

Iv had the glove box out and checked all the little motors they all appear to be moving when i press different things and appear to getting a full range of movement. The drivers side is no different. I cant see anything thats either sticking or not moving fully. Theres three little motors on either side with the exception of the drivers side which has 4. One right near the bottom.

The one near the bottom hardly moves no matter what i press so its hard to tell what that one actually does. There are no diagrams from what i can find on the internet at the moment of the heater arrangement.

I also cant find alot of info on how the Dual zone climate control works on the A6 Avant 3.0 TDI 2012? Does it have one heat exchanger and then it splits that heat exchanger in half for either side?

I felt the pipe work going into the heat exchanger and they are getting hot. I can feel the inlet and tell which is the outlet due to it being slightly cooler then the inlet.

The heater control valve on these appears to be only one solenoid meaning it only allows hot water to the heater matrix or not unlike the other c6 that appears to have two solenoids on it.

is it possible that the heater matrix is blocked? The inlet and outlet to the heater matrix is on the passenger side so it seems more likely that the drivers side is the side that would be more likely to get blocked? Or does the heater matrix only have one continuous pipe so if it was to get blocked any where along the length it would cool down the outlet significantly?

Am i missing another little motor thats controlling the heat side of things?

Because of the way this climate control works they all seem to move a little depending on what you press. At least two move when just controlling the heating side of things.

iv taken some photos of the drivers side.

20181211_145818.jpgInked20181211_145804_LI.jpg


Any help would be great thanks

[Gmonster]

Have you scanned for any error codes. The dual climate control is complicated with a number of sensors that could be sending the wrong data to the system that controls the motors.. a scan would give you a starting position.. etc..


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[MFGF]

Does this post help?

Dual Zone Climate control not working

MF.

[Gmonster]

Or this post... I had heating issues... turned out to be the solenoid valve... it was a bit of a journey to get it resolved..
Best Settings for A/C & Heating Controls
Question Best Settings for A/C & Heating Controls


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[Buckle]

Hi
my bitdi has the exact same issue as Craig.
left vents very hot (60 deg.c vcds) right vents much cooler (30 deg.c vcds).
same issue in the rear.

vcds reports no errors.

heater control valve on the passenger side appears to be work. Hot water flowing through both inlet and outlet pipes.
all vents/flaps work. All vents can be turned on and off using the climate control keys.

Any help would be much appreciated.

[Guestatron]

Hi all.
Did anyone ever get to the bottom of this heating problem?

[Gmonster]

See few posts back. My issue on the 2.0 tdi engine was the heating solenoid valve; part N82... part number as per previous post.


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[Guestatron]

Great thanks, will check that out now.

[Buckle]

Hi
The heating solenoid valve is under the bonnet on the near side by the screen watch bottle. I did a test on my valve and all appeared to be working. I also flushed my engine coolant and the cabin heat exchanger at the time using the pipes into/out of the solenoid valve and the problem resolved itself. I did notice recently the drivers side isnt has hot as the passengers side which is really annoying.

Do you have vcds to confirm your hvac temperatures are reading working correctly?

[Gmonster]

The solenoid valve issue that I had was that the valve was not working; stuck closed/open.

This was picked up on a VCDS/Carista scan; see pic.


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