[tilt]

Car: 2015 Jetta TDI DSG Highline Facelift model with automatic climate control, run 54000+ kms, .

This is the second problem that my car has that no one seems to have heard of and no other car but mine has ever had. It happens as though it is on a pre-programmed schedule, only in the mornings.

I usually leave early in the morning (latest by 6 a.m.) on long drives. The outside temperatures are usually around the 20-21 degree mark. The AC at that time works absolutely fine, lots of blow and lots of cooling.

After about an hour or so, when the outside temperature is around 23-25 degrees Celsius, and I have covered around 100+ kms, the AC just stops blowing. The fan just stops without any warning.

I touch the vents themselves, they are still cool to the touch, but not even the slightest whisper of any fan movement. So, to my layman’s brain, it appears to be that the compressor itself is working and the issue is with the blower part of the unit. However, as will be seen below, that doesn’t seem to be the issue either.

I move there AC from automatic to manual mode and fiddle around with the fan speed knob, turning it on to full speed etc. The sound is there, as though the fan is on and blowing, but there is no blow at all. All sound, no action

Nothing I do will make the fan blow.

There are no warning lights in the instrument cluster, no indication that the AC is not blowing, other than that there is no moving air.

I then stop for breakfast or a bio-break, and turn the car on when ready to leave. The AC works beautifully, fan blows with gusto, and stays on throughout the day, irrespective of how hot or cold or dry or humid the outside is, and irrespective of how long and how far I drive.

So, the only observation I have is that the AC fan has a recurring appointment between 7 a.m. and 9 a.m. that takes it away from its job onto some personal business, and then it’s back and serving me faithfully.

The only way to get the fan back on is to stop, turn the car off and on (maybe it runs Windows????? LOL)

The problem happens ONLY in the morning, and that too only after driving for an hour or so; and then never happens again, until I go on another long trip.

The car does not get used in the city. The only city use the car gets is en-route to the highway.

Tell me I am not going mad, and that there genuinely could be reasons for this kind of weird behaviour.

Thanks and cheers

[androdev]

If you hear the blower fan sound (the sound should get louder as you dial up the blower speed) then it must be the flaps that are messed up. Try in heater mode to see if you get air flow. In the heater mode, the air comes out of the bottom vents unless you fiddle with air con dials to switch to top vents, etc.

Edit: it is easy to remove the air-con cabin filters and be able to inspect both the blower and evaporator coil.

[Jaggu]

Classic case of icing up is my suspect. AC cooling is more than what the blower can disperse off the grill, leading to icing up of AC gas. When you stop for a while, it de-freezes and starts circulating again. You can check this by just switching off the compressor switch off (leave it off for about 5 mts) while keeping fan on and then switching On just the compressor switch.

If it works then next thing to check is how the dust filters are? are they clean and and not obstructing any airflow, if so replace the filter and see how it behaves. If not you need to get a clean up of the AC cooling coil (inside the dash) along with the blower assembly.

[dhanushs]

If the blower sound is normal and it's just the blow that is not there, your problem might be the evaporator coil getting all iced up.

It's due to a faulty thermostat switch.

[itwasntme]

Originally Posted by Jaggu

Classic case of icing up is my suspect. AC cooling is more than what the blower can disperse off the grill, leading to icing up of AC gas. When you stop for a while, it de-freezes and starts circulating again. You can check this by just switching off the compressor switch off (leave it off for about 5 mts) while keeping fan on and then switching On just the compressor switch.

If it works then next thing to check is how the dust filters are? are they clean and and not obstructing any airflow, if so replace the filter and see how it behaves. If not you need to get a clean up of the AC cooling coil (inside the dash) along with the blower assembly.

Exactly what I used to face in my Aveo on long drives and the way to fix it was what you captured. I eventually had to change both the coil and the switch.

[SS-Traveller]

As Jaggu rightly said, the cooling coil inside the dashboard is icing up. It could be the thermostat probe/sensor that is faulty, or there can be dust/muck accumulation over the coil.

Two queries:
- Is the weather in your area very humid?
- Are you allowing the automatic system to choose fresh air / recirculation mode on its own, or are you forcing it manually to stay in one of the modes?

[dkaile]

I have experienced cooling coil icing up in 2 conditions -

1) It is choked and requires a thorough clean up or
2) The refrigerant gas is low

Hope it helps. Cheers...

[Sutripta]

Low on gas is the most likely cause. Counterintuitive.

Regards
Sutripta

[Lord Lucan]

I had the exact same problem in my Vista and it was resolved by cleaning the air filter. I encountered this problem only on long drives.

Possible rootcause: Water condensation with dust clogged the air filter. When this happens you can only "hear" the blower

[MAS]

Originally Posted by Jaggu

Classic case of icing up is my suspect. AC cooling is more than what the blower can disperse off the grill, leading to icing up of AC gas. When you stop for a while, it de-freezes and starts circulating again. You can check this by just switching off the compressor switch off (leave it off for about 5 mts) while keeping fan on and then switching On just the compressor switch.

If it works then next thing to check is how the dust filters are? are they clean and and not obstructing any airflow, if so replace the filter and see how it behaves. If not you need to get a clean up of the AC cooling coil (inside the dash) along with the blower assembly.

The icing is the problem here. I had this same problem in my erstwhile Santro. This happens when the gas in the Aircon system is low. Please have this topped up and everything will be back to normal.

[2000rpm]

Agree with above diagnosis from multiple members. Had the same issue with my Civic and at a hotel in Mumbai (Hotel Shalimar). The AC in the hotel was literally throwing out pieces of ice .

[vaskarnag]

Hi,

This happened to me too on the Jetta (2014) occasionally (once a month). Not on long drives. But when returning home on a bumper to bumper traffic for hours. And when the outside temperature is slightly more than the inside setting. Yes it does not work in a manual too then.
Swictching on and off the engine helps.
However this seems to have disappeared now. I did not complain thinking this to be some SW bug

[amit_shimla]

Similar issue cropped up in my brother's Chevrolet Sail which was fixed by replacing the resistance circuit to the blower. A simple 500 rupee fix took only 5 minutes. I hope this the problem in your case as well.

[pramodpk]

Originally Posted by tilt

After about an hour or so, when the outside temperature is around 23-25 degrees Celsius, and I have covered around 100+ kms, the AC just stops blowing.

As others have pointed out, this seems to be an issue with the thermostat. I had the same issue in my Fiesta. It was resolved after the thermostat was replaced.

[asethi]

I don't know if it's same but similar problem happened in my Swift. Background - it started an year ago on a trip to Kodaikanal when AC suddenly stopped cooling after an hour or so of driving. After I came back AC cooling was ok most of the time as my commute was short. Then it started to stop cooling randomly and service folks refilled the AC gas and chill was back. Then few months back suddenly my AC completely stopped (only fan was running) and I could hear compressor cutting off & on and car overheated. I stopped the car and let it cool down before taking to MASS. They diagnosed some valve had gone kaput but the real reason was my radiator fan not working on low speed and only used to kick-in when engine was getting over heated and fan started at high speed. So basically it was slow poisoning in the engine valve that it used to overheat and cutoff the AC before radiator fan kicked back in to cool it down but not completely as it didn't work in low speed. And now all is well after replacing the radiator fan - AC runs perfect and engine doesn't overheat.

So get your radiator fan checked, it might be the reason if you go by my problem.