Air con: only blowing very hot or very cold

[Tinlad]

Hello!

Completely new here, so I hope I'm following the correct etiquette for asking questions. I've searched (both the forum and Google) for an answer prior to posting and haven't found anything.

I've got a 2003 Ibiza S (1.4 petrol) with a bit of a problem with the air con:
- If it's set to the minimal temperature, I get very cold air.
- If it's set to any other temperature, I get extremely (uncomfortably!) hot air.

The air con is controlled via three manual dials. All the controls except temperature seem to work as they should. The problem exists whether the 'AC' control is on or off.

My hypothesis is that it's not detecting the cabin temperature accurately, and thinks that it's much colder than it is, and therefore shovelling out air that's as hot as it can manage. The exception is when it's on the minimum setting, in which case it ignores the cabin temperature and just gives cold air.

Does that sound plausible? If so, any suggestions for a fix?

Many thanks in advance for any help you can give.

Cheers!

 

[RUM4MO]

Sounds like your A/C is the manual one, the automatic A/C systems have a flap motor for adjusting the temperature. On these automatic systems, the positional feedback potentiometer track gets dirty so can at certain well used positions, be open circuit. The track at the ends of travel, ie HIGH and LOW temperatures usually remain clean and so work okay. If this is the case, without removing this flap motor and cleaning the track area, not easy, then the only way forward is to replace the flap motor and that means that the new motor needs "basic setting" carried out. Maybe try working the temperature control from one end to the other a lot of times as this can clean the track up a bit. Of course if manual A/C does not have a flap motor then something else must be wrong. Maybe, if no flap motor is involved, it is what ever is on that control knob, ie potentiometer that is faulty.

 

[Tinlad]

Thanks for your reply!

Yes, I believe that my A/C system is manual. I can't post an image of the controls (not enough posts yet), but based on visuals I think that the part number is 6L0820045.

It's a good shout that it may be the pot at fault. I guess I might be able to test this with a multimeter? Any idea if they can be cleaned out at all?

... or I guess I could just buy a complete replacement set of control dials and swap them out. Looks like I could get some for about £25 on eBay which isn't too bad. Any experience of whether they're easy to get in/out?

Thanks again.

 

[RUM4MO]

No, I don't know how it comes apart - I'm a Polo 9n, Ibiza Mk5 and S4 B8 person, maybe time to buy a Haynes book. I'd hope that you could check the pot using a DMM. Trouble, in my mind, of buying used parts from ebay, if it is this knob that is faulty, then how much if any life is left in the used one you could buy - though I don't always listen to my own advice!(could not have the same fault could it - oh yes it could)

 

[Tinlad]

I'll see if I can get in there with a multimeter to check it out, and to confirm the part number.

I realise that eBay can be a minefield, but I may just risk it - it's this time of year that the problem gets infuriating, as the hot air's too hot, but the cold air's too cold. I spend half my time switching the fans on and off to try and maintain a comfortable temperature (and clear windows!).

Thanks again for the advice, it's much appreciated.

 

[Blanco92]

Mine does exactly the same thing intermittently! And to be honest, it's done it for years. I find if I cycle the temp control knob from full cold to full hot, or the blower speed from zero to full, it goes away sometimes. Then again, sometimes it doesn't, and the only way to stop myself fainting is to open the windows and let the hot air out!

The problem does lie with the flap position motor, when I scan my car with VCDS I get 3 fault codes relating to it. The only reason I've never fixed it, is because I don't know where this flap motor is!

So my question is this... Where is it?

 

[Tinlad]

It's good to know I'm not alone!

I haven't found a Ibiza specific guide to replacing the motor, but I found one for a '03 Polo (I assume it'd be similar), and it doesn't look like a simple task... but I am something of a novice with these things.

The other thing I haven't been able to work out is whether simply replacing the hardware will fix the issue, or whether I'd need all the VCDS malarky to reset the software side...

 

[Blanco92]

I would imagine, a fully functional flap motor would fit straight in and work. No VCDS malarkey required. However, my car has been doing this since I bought it at 26k miles, so going for a second hand motor from a car that has probably done more miles... Doesn't seem a good idea to me!

I've tried all the basic settings stuff in VCDS on mine, doesn't make a difference, it's too far gone I reckon.

I don't know how much a new motor is, if it was cheap enough I'd get one. But I doubt they're that cheap. I'm still recovering from the shock of a new window regulator at over £85 on mine! And it happened months ago!

 

[RUM4MO]

I would imagine, a fully functional flap motor would fit straight in and work. No VCDS malarkey required. However, my car has been doing this since I bought it at 26k miles, so going for a second hand motor from a car that has probably done more miles... Doesn't seem a good idea to me!

I've tried all the basic settings stuff in VCDS on mine, doesn't make a difference, it's too far gone I reckon.

I don't know how much a new motor is, if it was cheap enough I'd get one. But I doubt they're that cheap. I'm still recovering from the shock of a new window regulator at over £85 on mine! And it happened months ago!

I think that is also roughly the price for a flap motor, and yes, even a new motor will need basic setting carried out so that the controller knows the end stop voltages.