Fan Blowing but no circulation of AC or Heat
11-01-2017, 03:41 PM
#1
AudiWorld Member
Thread Starter
Fan Blowing but no circulation of AC or Heat
2006 A8L
Issue started this summer, would be blowing ice cold air and then no air. The fan is blowing, but nothing is coming out of the vents.
After car is off for a while then it will work.
Now with heat on it will start OK on car start, but then the circulation stops, but I can hear the fan blowing.
Any ideas where to start?
during the summer I thought it was the freon, but it was charged OK no leaks
now as it has gotten cold, I thought it was a blockage from searching the forum, but nothing points toward that.
the fluid was drained and replaced this summer, I just has an engine replacement, water pump, timing belt etc.
Any direction i can check for fan blowing, but no air coming out of vents front or back?
Thanks
Issue started this summer, would be blowing ice cold air and then no air. The fan is blowing, but nothing is coming out of the vents.
After car is off for a while then it will work.
Now with heat on it will start OK on car start, but then the circulation stops, but I can hear the fan blowing.
Any ideas where to start?
during the summer I thought it was the freon, but it was charged OK no leaks
now as it has gotten cold, I thought it was a blockage from searching the forum, but nothing points toward that.
the fluid was drained and replaced this summer, I just has an engine replacement, water pump, timing belt etc.
Any direction i can check for fan blowing, but no air coming out of vents front or back?
Thanks
11-04-2017, 08:18 AM
#2
AudiWorld Senior Member
Hello C,
Have you checked your cabin air filter, also check that the fresh air intake is working properly, as in if while someone was doing the engine swap they unplugged the recirculating/fresh air flap motor, I know on my Bentley build I have a issue with were the flaps attach to the motor shaft, and if the HVAC is not set to recirculate I have no air at all, unless I open the flaps by hand, or place the HVAC system in recirculating mode, then I go from no air at all, to full blast airflow.
Have you checked your cabin air filter, also check that the fresh air intake is working properly, as in if while someone was doing the engine swap they unplugged the recirculating/fresh air flap motor, I know on my Bentley build I have a issue with were the flaps attach to the motor shaft, and if the HVAC is not set to recirculate I have no air at all, unless I open the flaps by hand, or place the HVAC system in recirculating mode, then I go from no air at all, to full blast airflow.
11-05-2017, 03:41 AM
#3
AudiWorld Member
Thread Starter
Thanks I'll check the cabin air filter, but would that block air flow after it has been blowing?
I tried to set to recirc and then back to fresh the air flow did not change.
Where would i find these flaps to open by hand if i need to?
I tried to set to recirc and then back to fresh the air flow did not change.
Where would i find these flaps to open by hand if i need to?
11-05-2017, 06:55 AM
#4
AudiWorld Senior Member
Response in Red .
2006 A8L
Issue started this summer, would be blowing ice cold air and then no air. The fan is blowing, but nothing is coming out of the vents.
After car is off for a while then it will work.
Now with heat on it will start OK on car start, but then the circulation stops, but I can hear the fan blowing.
Any ideas where to start?
Are you 100% sure the fan is still running, this looks to be a faulty fan motor, as a dying fan motor will work for a short period of time after a rest, then die again, and start again, until it dies completely.
during the summer I thought it was the freon, but it was charged OK no leaks
Freon has nothing to do with airflow....
now as it has gotten cold, I thought it was a blockage from searching the forum, but nothing points toward that.
the fluid was drained and replaced this summer, I just has an engine replacement, water pump, timing belt etc.
Again, blockage of coolant in the 2 heater cores would have nothing to do with airflow, if coolant was blocked, you would just have cold air instead of hot.
Any direction i can check for fan blowing, but no air coming out of vents front or back?
Yes, remove the cabin air filter, and with the flaps open, as in fresh air intake (not in recirculating mode) observe that the squirrel cages are indeed spinning, and continue to spin when you think you still hear the fan running.
Thanks
Issue started this summer, would be blowing ice cold air and then no air. The fan is blowing, but nothing is coming out of the vents.
After car is off for a while then it will work.
Now with heat on it will start OK on car start, but then the circulation stops, but I can hear the fan blowing.
Any ideas where to start?
Are you 100% sure the fan is still running, this looks to be a faulty fan motor, as a dying fan motor will work for a short period of time after a rest, then die again, and start again, until it dies completely.
during the summer I thought it was the freon, but it was charged OK no leaks
Freon has nothing to do with airflow....
now as it has gotten cold, I thought it was a blockage from searching the forum, but nothing points toward that.
the fluid was drained and replaced this summer, I just has an engine replacement, water pump, timing belt etc.
Again, blockage of coolant in the 2 heater cores would have nothing to do with airflow, if coolant was blocked, you would just have cold air instead of hot.
Any direction i can check for fan blowing, but no air coming out of vents front or back?
Yes, remove the cabin air filter, and with the flaps open, as in fresh air intake (not in recirculating mode) observe that the squirrel cages are indeed spinning, and continue to spin when you think you still hear the fan running.
Thanks
Thanks I'll check the cabin air filter, but would that block air flow after it has been blowing?
I would hope that the filter would not be that clogged to block all airflow, But I am not sure if you followed what I was getting at, the filter only comes into play when taking outside air into the cabin, if when you start the vehicle the system is in recirculating mode then the flaps would be closed and the filter would not be in use and the system gets its air from inside the vehicle to either cool or warm quicker, when the HVAC system switches over to fresh air mode after a period of time the flaps would open and allow fresh air in through the filter into the system, now, if the filter is totally clogged, or the flaps are stuck closed as in jammed as another member here just had, ( a plastic cover for the ECM jammed over the fresh air intake flaps) or the flaps motor is shot, then when the system is looking for outside air to feed it, it has no air at all, hence when manually put in recirculating mode and light on, on the HVAC controls, you would have airflow, that is of course if you have a fully functional blower motor....
I tried to set to recirc and then back to fresh the air flow did not change.
How long did you wait before turning off recirculating mode ?
Where would i find these flaps to open by hand if i need to?
See picture, and be gentle, do not force the flaps, just check for their operation first.
I would hope that the filter would not be that clogged to block all airflow, But I am not sure if you followed what I was getting at, the filter only comes into play when taking outside air into the cabin, if when you start the vehicle the system is in recirculating mode then the flaps would be closed and the filter would not be in use and the system gets its air from inside the vehicle to either cool or warm quicker, when the HVAC system switches over to fresh air mode after a period of time the flaps would open and allow fresh air in through the filter into the system, now, if the filter is totally clogged, or the flaps are stuck closed as in jammed as another member here just had, ( a plastic cover for the ECM jammed over the fresh air intake flaps) or the flaps motor is shot, then when the system is looking for outside air to feed it, it has no air at all, hence when manually put in recirculating mode and light on, on the HVAC controls, you would have airflow, that is of course if you have a fully functional blower motor....
I tried to set to recirc and then back to fresh the air flow did not change.
How long did you wait before turning off recirculating mode ?
Where would i find these flaps to open by hand if i need to?
See picture, and be gentle, do not force the flaps, just check for their operation first.
11-16-2017, 06:16 AM
#6
AudiWorld Member
Thread Starter
Sorry had family emergency and late nights at work.
I will check this weekend and update.
For right now the heat is working.
I only turn it on or off and don't adjust the temp or mess with the venting.
Only thing I do right now is turn the vent off on the driver side window when i get too hot and open a window.
Also, I did notice that the rear vents do not have any air blowing out of them. I will check that this weekend as well. hopefully it is just a fuse.
I will check this weekend and update.
For right now the heat is working.
I only turn it on or off and don't adjust the temp or mess with the venting.
Only thing I do right now is turn the vent off on the driver side window when i get too hot and open a window.
Also, I did notice that the rear vents do not have any air blowing out of them. I will check that this weekend as well. hopefully it is just a fuse.
11-19-2017, 03:01 PM
#7
AudiWorld Member
Thread Starter
OK checked the cabin air filter, recirc flaps and the fans "hamster wheels"
The cabin air filter was totally disgusting so I'm going to replace that tonight.
the flaps were not stuck, i open and close them about 20 times and then had my daughter come out and press the button while I took a video to see if anything was going on.
Lastly the fan motor was moving. did not slow down or stop during the test.
The car was up to temp, i had just gotten back from a trip to the store and raced a brand new Jag a couple of lights. *side bar i was pulling away from the jag and i could hear their engine working like they were giving it all the gas, proud of the A8 for showing its strength"
Like i said in previous post it was working and i did not change any settings once it got cold to make sure that I had heat in the car.
I'll start changing the settings to see if i can pinpoint when it happens
The cabin air filter was totally disgusting so I'm going to replace that tonight.
the flaps were not stuck, i open and close them about 20 times and then had my daughter come out and press the button while I took a video to see if anything was going on.
Lastly the fan motor was moving. did not slow down or stop during the test.
The car was up to temp, i had just gotten back from a trip to the store and raced a brand new Jag a couple of lights. *side bar i was pulling away from the jag and i could hear their engine working like they were giving it all the gas, proud of the A8 for showing its strength"
Like i said in previous post it was working and i did not change any settings once it got cold to make sure that I had heat in the car.
I'll start changing the settings to see if i can pinpoint when it happens
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11-19-2017, 04:11 PM
#8
AudiWorld Super User
It isn't clear to me from skimming this if your HVAC control panel/head is working or not. Does it respond when you push each button? At all? Correctly in all cases.
Reason I ask is in turn if it seems like it might be at all electrical to scan the HVAC with VCDS. I noticed at some point when I ran a general scan that I had a code on mine for rear control head (back seat one). About the same time I noticed I could not get it to change temperature from the back, though I could from the front (with the rear control function in the settings area). Long story short, bought a new rear control head off eBay, put it in and all good. Rear heads don't need dealer coding. Front ones might.
Reason I ask is in turn if it seems like it might be at all electrical to scan the HVAC with VCDS. I noticed at some point when I ran a general scan that I had a code on mine for rear control head (back seat one). About the same time I noticed I could not get it to change temperature from the back, though I could from the front (with the rear control function in the settings area). Long story short, bought a new rear control head off eBay, put it in and all good. Rear heads don't need dealer coding. Front ones might.
11-19-2017, 05:21 PM
#9
AudiWorld Member
Thread Starter
It isn't clear to me from skimming this if your HVAC control panel/head is working or not. Does it respond when you push each button? At all? Correctly in all cases.
Reason I ask is in turn if it seems like it might be at all electrical to scan the HVAC with VCDS. I noticed at some point when I ran a general scan that I had a code on mine for rear control head (back seat one). About the same time I noticed I could not get it to change temperature from the back, though I could from the front (with the rear control function in the settings area). Long story short, bought a new rear control head off eBay, put it in and all good. Rear heads don't need dealer coding. Front ones might.
Reason I ask is in turn if it seems like it might be at all electrical to scan the HVAC with VCDS. I noticed at some point when I ran a general scan that I had a code on mine for rear control head (back seat one). About the same time I noticed I could not get it to change temperature from the back, though I could from the front (with the rear control function in the settings area). Long story short, bought a new rear control head off eBay, put it in and all good. Rear heads don't need dealer coding. Front ones might.
installed the CAF and changed temp all is working ok so far will see if it works tomorrow after the change. Have an hour commute in the morning.
control panel buttons works all buttons pushed.
ill scan the the HVAC Codes tomorrow and report back
11-19-2017, 06:35 PM
#10
AudiWorld Senior Member
Hello C,
I just want to be clear on your comment, when you said "the flaps were not stuck, i open and close them about 20 times", I take that you mean you pushed the recirculate button about 20 times and the fresh air flaps operated on their own, not that you opened and closed them by hand, as the flaps should not move freely by hand, so, if the flaps operated on their own then let's see what the HVAC scan shows tomorrow, there is the same type of setup for the recirculating flaps on the inside of the vehicle as shown in the diagram of the HVAC suitcase, so, for all air on the left and right to stop blowing at any giving time, you would have to have either the fresh air flaps failed closed while the recirculating flaps are properly closed looking for fresh outside air, or the fresh flaps are properly closed and the recirculating flaps are failed close and not supplying any recirculated airflow, or a number of the other flaps all failing at the same time to stop all airflow to all ducts as you said it did, SO, how many miles on your 06, and when was the last time the blower motor was replaced, as what you describe sounds like a failing blower motor, although, you say you can hear it running, again, hopefully the scan will show something..
.
I just want to be clear on your comment, when you said "the flaps were not stuck, i open and close them about 20 times", I take that you mean you pushed the recirculate button about 20 times and the fresh air flaps operated on their own, not that you opened and closed them by hand, as the flaps should not move freely by hand, so, if the flaps operated on their own then let's see what the HVAC scan shows tomorrow, there is the same type of setup for the recirculating flaps on the inside of the vehicle as shown in the diagram of the HVAC suitcase, so, for all air on the left and right to stop blowing at any giving time, you would have to have either the fresh air flaps failed closed while the recirculating flaps are properly closed looking for fresh outside air, or the fresh flaps are properly closed and the recirculating flaps are failed close and not supplying any recirculated airflow, or a number of the other flaps all failing at the same time to stop all airflow to all ducts as you said it did, SO, how many miles on your 06, and when was the last time the blower motor was replaced, as what you describe sounds like a failing blower motor, although, you say you can hear it running, again, hopefully the scan will show something..
.