Climate Control problem - please help

[pds999]

I bought a used Audi A4 Avant 1.9 TDi (2002 plate) a couple of weeks ago and the climate control (dual zone) is playing up. Basically it does give out cold air when on LO setting but as soon as you raise the temp to 18 or more and set it to AUTO it spews out hot air from the vent under the windscreen and the cabin heats up to close to 30 degrees. I have tried experimenting with every setting but there is no happy medium, it's either cold or hot and the car fills up with condensation on longer journeys.

I have taken it to a main Audi dealer who ran a diagnostic and said nothing was wrong. I am now at a loss as there most definitely is something wrong.

Anyone have an idea what could be wrong? I was thinking the temp sensor but the diagnostic said it was fine. The air on LO is chilled (not greatly so but still chilled) so I have kind of ruled out it needing re-gasing.

I am open to any suggestions...

[sbuk73]

I've not really had any issue with the dual zone climate. If when you set the temperature to 18 as I would expect to see on the display when set to AUTO the fan speed should go up and when it senses then the cabin temperature is near that the fans should slow down just to maintain. Do both the zone temperatures read the same ? I'm sure you've done the keeping the AUTO button pressed for 3 seconds thing just to sync them up. Other than that I have no idea - perhaps someone else here has reported something similar previously.:confused:

[pds999]

I've not really had any issue with the dual zone climate. If when you set the temperature to 18 as I would expect to see on the display when set to AUTO the fan speed should go up and when it senses then the cabin temperature is near that the fans should slow down just to maintain. Do both the zone temperatures read the same ? I'm sure you've done the keeping the AUTO button pressed for 3 seconds thing just to sync them up. Other than that I have no idea - perhaps someone else here has reported something similar previously.:confused:
Thanks for the reply. I have an A3 as well and in that I just set it to 21 (on AUTO) and leave it. In the A4 however, if you do that then warm/hot air constantly comes out of the vent under the windscreen and the cabin just becomes way too hot. I have read somewhere that could be an A4 design fault and if you leave it long enough it will start to cool, but it hasn't done that with me. It almost seems either like warm air is wrongly being pumped constantly to the front vent (under the windscreen) or the temp sensor is wrong and it thinks it needs to be much hotter. But the Audi diagnostic showed nothing wrong.

Does the A4 just have a terrible climate control and should I expect this? i.e. do I need to trade it in for a different car? I have two dogs so can't have a car that doesn't have controllable climate control.

[sbuk73]

To be honest I've had my A4 for 5 years and never used the AUTO setting except in Summer on occasion, I have 2 vent settings set - have the air pointing UP and DOWN and not in my face. Why don't you see what happens with your temperature test if you set the vent setting just to UP/TOP position. Set the temp LOW just to confirm cold air does come out of it. Also erm, while set to AUTO, you have a front screen demister button which blasts the front windscreen - turn that on for a few seconds then switch off just to see if that normalises temperature back to 18 etc.

DUnno random stupid ideas ...I know.

[sbuk73]

The Climate in the A4 is good - its miles better than any BMW 5 series I've sat in and it is one feature over normal aircon I must have when buying a car.

[pds999]

To be honest I've had my A4 for 5 years and never used the AUTO setting except in Summer on occasion, I have 2 vent settings set - have the air pointing UP and DOWN and not in my face. Why don't you see what happens with your temperature test if you set the vent setting just to UP/TOP position. Set the temp LOW just to confirm cold air does come out of it. Also erm, while set to AUTO, you have a front screen demister button which blasts the front windscreen - turn that on for a few seconds then switch off just to see if that normalises temperature back to 18 etc.

DUnno random stupid ideas ...I know.
Interesting, I'll give anything a go. The car is with the dealer still while they "look into it" but I am convinced they'll simply say nothing is wrong even though the technician did concede that it shouldn't be blowing hot air out the windscreen vent when the temp was on 18 AUTO.

As for cold air on LO, yes it does come out cold (colder than air temp) but not as chilled as in my A3 which made me suspect the refridgeration/gas unit. But if that was the case, not sure why it would spew out hot air from the front vent.

I know Audi can make decent climate control systems because my A3 (also 2002 plate) is spot on. I just wondered if the A4 version is a dud and this is what I should expect.

[kenney]

Hi The climatronic in the a4 is one of the best, and has very few problems.The workshop can do a final control diagnosisems,which tests every working unit,and a basic setting,and then do a fault code read,and if there is anything wrong it will show up on the diagnose,

[pds999]

Hi The climatronic in the a4 is one of the best, and has very few problems.The workshop can do a final control diagnosisems,which tests every working unit,and a basic setting,and then do a fault code read,and if there is anything wrong it will show up on the diagnose,

Thanks. They have done a basic diagnosis today which showed nothing so said tomorrow they will test the pressures (of the hoses, etc) and do some more tests.

If nothing shows up, what do I do then? There is most definitely something wrong as I know what a working Audi climate control should be like (my A3 is spot in) and this is most definitely not working properly.

[kenney]

Hi (If nothing shows up, what do I do then?) try a workshop that knows what they are doing, with the fault you describe,there is something wrong.

[pds999]

Hi (If nothing shows up, what do I do then?) try a workshop that knows what they are doing, with the fault you describe,there is something wrong.
Yep, think you are right. I'll see what my local dealer comes up with and try somewhere else if I get no joy. The alternative is selling the car and buying a different one which seems drastic. But with two dogs (one who is a husky who obviously doesn't like warm temps), climate control is a must.

[pds999]

Just had a call from Audi. They have isolated the fault but the only way to repair it (apparently) is a whole new climate control system. Cost: £400 plus labour (around £800 in total). Ouch.

[nickynibbles]

Just had a call from Audi. They have isolated the fault but the only way to repair it (apparently) is a whole new climate control system. Cost: £400 plus labour (around £800 in total). Ouch.

Thats not exactly what i'd call isolating the fault!! I'd say it was more of a cop out in that they dont know whats wrong but changing the system should solve it! I'd go back to them and ask for an exact description of the fault they have found and why it needs a new system!

[pds999]

Thats not exactly what i'd call isolating the fault!! I'd say it was more of a cop out in that they dont know whats wrong but changing the system should solve it! I'd go back to them and ask for an exact description of the fault they have found and why it needs a new system!
No and the saga gets worse. After saying to the girl on the phone yesterday that I wanted them to order the part, I changed my mind overnight and asked to cancel and I would get a 2nd hand one and fit myself. Audi say they can't cancel and I still have to pay (as it is a "special part" apparently). So fair enough I thought, it was my fault for confirming they go ahead and order. Anyway now turns out that a "new" unit has to be coded to the car so I can't even fit myself. Might still work out cheaper to buy a used unit for £100 off eBay and fit myself and sell on the new one.

[kenney]

Hi Normaly these units are coded from the factory.Should it need recoding,you have the code you need on the old unit.

[pds999]

Hi Normaly these units are coded from the factory.Should it need recoding,you have the code you need on the old unit.
Thanks Kenney. Do you know how I get the code from the old unit if the new one does need recoding? Does it require a laptop/diagnostic software to be plugged in or can I access the code myself?

[kenney]

Yes you need a vag.com or similar diagnostic tool.

[RodCouncil]

Try a specialist but I would say it needed a regass, mine was doing something similar but once regassed it was as cold as ice on lo and cold on 18.

[mac1]

Hi pds999
I have similar problem which started yesterday on my 2002 A4. I have had my car just two weeks and all was working fine until now. Previously the engine and heater were warming up very quickly. 1 mile from cold to reach 90 degrees. Now the heater is only kicking out ice cold air on the drivers side regardless of settings. The passenger side is the same except it does get ever so slightly warmer when set to 'HI' with full fan speed. I also think it took longer for the engine to warm today although it did settle at 90 degrees c as usual. Coolant level is normal. Any ideas? Matrix?

:1zhelp:

[mac1]

Bizarre! all working fine this morning after a 30 second blast of cold air it suddenly began to warm up and is now working as normal again. I can only assume it had an air lock? Let's hope it continues to work properly.

[hagis]

Sounds like one of the actuators controlling the air flow in your dashboard is sticking. It happens in my car, I've not got round to fixing it as it's so intermittent. I try and turn the heat up and down now and then to stop it sticking.

[justin99]

Hi there.
I just bought an 03 A4 avant and have exactly the same problem! The vent under the windscreen mostly blows hot when set to 18. Very strange! I havnt asked the dealer to do a dianostic yet - doesnt sound promising. Did you get anywhere with this issue?
justin

[pds999]

To be honest I didn't get very far no. My Audi dealer found nothing in the diagnostic and recommended a new climate control unit (the one that sits under the stereo) which they would charge £800 for and to fit. I decided sod that and got one from eBay for £25 and tried that but made no difference. I then unscrewed the high pressure sensor (Audi call it a thrust sensor) and replaced that but no difference. I also had it re-gased which made it colder in general but didn't solve the warm air from the front vent issue. I have found that if you set it to 18 deg and leave it 10 mins or more then the temp does come down in the front vents and it does get cooler, but not hugely so.

It might simply be a design fault. I am selling the car anyway so have given up on it!

My advice is NOT to take it to an Audi dealer (who will try and sell you a whole new unt) but to find a recommended Audi independent garage in your area and ask them to test it.

[justin99]

thanks. most impressed by your persiverance though!!

justin