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Discussion Starter · #1 ·
I have a problem with air condition. It blows cool air but no warm / hot air no matter is it on manual or automatic mode.

What I have done so far is;
- Check that engine coolant level is ok
- Check that all the fuses are ok
- Monitored coolant temperature which is between 85-89 Celsius while driving

It is also worth to mention that ambient temperature sensor is not always giving the right values.

Is the coolant temperature too low for thermostat to open? It is starting to get cold here in Finland, any hints how to go from here would be pretty much appreciated.
 

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First, seeking clarification, are you stating that what we in the U.S. (and elsewhere) would call the air conditioning or A/C is not cooling appropriately? Or is it that "the heat" doesn't seem to work? In other words, are you having trouble cooling off the cabin air, warming it up or both?

As it happens, my ambient temperature sensor occasionally does not function correctly. While this has not yet happened to me, it is my understanding based on my review of relevant discussion threads here that a dysfunctional ambient sensor can indeed feed faulty data to the system that regulates cabin temperature. I have a replacement ambient sensor that is awaiting replacement. Perhaps replacing yours will solve your issue but I'm sure that more experienced posters will have much to add to the discussion.
 

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What A2S40guy says is correct. If the ambient temperature sensor is bad, it will cause the auto-climate control to not function properly. The easiest way to check is to look at the outside temperature displayed on the dash and see if it matches the true outside temperature. Usually a bad sensor will read very low. This causes the AC to blow warm.

The auto-climate control also has an cabin temperature sensor located in the dash just to the left of the center console. It can get clogged with dust or just fail and it too will cause issues.

The way the system works is, hot engine coolant is always flowing through the heater core. The temperature is adjusted by a servo controlled damper door that directs and varies the amount of air flowing over the heater core vs the AC core. Sometimes the servos in our cars get out of sync. VIDA/DICE can be used to re-calibrate. Servos have also been known to fail.
 

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Discussion Starter · #4 ·
Warming is the problem, I can get cold air but it wont blow warm air. Thanks for the tip, it seems that I need to examine this ambient sensor to see if it needs to be replaced.
 

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Discussion Starter · #5 ·
What A2S40guy says is correct. If the ambient temperature sensor is bad, it will cause the auto-climate control to not function properly. The easiest way to check is to look at the outside temperature displayed on the dash and see if it matches the true outside temperature. Usually a bad sensor will read very low. This causes the AC to blow warm.

The auto-climate control also has an cabin temperature sensor located in the dash just to the left of the center console. It can get clogged with dust or just fail and it too will cause issues.

The way the system works is, hot engine coolant is always flowing through the heater core. The temperature is adjusted by a servo controlled damper door that directs and varies the amount of air flowing over the heater core vs the AC core. Sometimes the servos in our cars get out of sync. VIDA/DICE can be used to re-calibrate. Servos have also been known to fail.
I examined the cabin temperature sensor and cleaned it from dust but unfortunately it did not fix the problem. Next I will check the ambient sensor and then if no luck I will proceed to ensure is servo / thermostat working.
 

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Do you get more heat if you turn the AC off? (just the AC, not the blower fan)
I had similar problems with my heat last winter, when i turned the AC on and blow up on the window it was not much heat at all, but if i turned off the AC and aimed the flow against the feet area it was hot again.
For me it was the AC clutch doing that, re-shimmed it and after that i got heat in all settings. (why/how it actually did work still astonish me :p )
 
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