Air conditioning wont work.
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Error codes from the AC module? A common problem one these models is an internal solenoid failing. There is no clutch, the solenoid is what controls AC on vs. off.
Does changing the fan speed do anything? Climatronic or manual control?
Does changing the fan speed do anything? Climatronic or manual control?
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Well if you have it checked by a qualified air con person then they should have checked all systems for that vehicle or was this done by a mate?
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I have problems with my 2009 Jetta air conditioner. It will not cool if heat soaked in a parking lot or sitting in the drive way. It will not cool until the road speed is high enough to push air through the condenser coil in the front.
The vag-com shows no errors, but the radiator fan does not speed up like I think it should.
Does anyone really know how the control computer works?
The pressures seem reasonable and can see the pressures in the VCDS.
The compressor is running and the pressure will go high when the cooling quits at low speed.
I thought that there was a high pressure switch that would run the fan at hgh speed, but it looks like the system reads the pressure though an analog sensor and the fan has PWM speed control.
I want to make the fan run at high speed to check the fan circuit and fan.
The pressure I have seen on the VCDS is about 18 BAR. and when the condensor is not getting cooling air needed this would be reasonable.
I think that the fan would run in high speed under these conditions.
Does anyone know how to check the fan with the VCDS?
Thanks,
JDB
The vag-com shows no errors, but the radiator fan does not speed up like I think it should.
Does anyone really know how the control computer works?
The pressures seem reasonable and can see the pressures in the VCDS.
The compressor is running and the pressure will go high when the cooling quits at low speed.
I thought that there was a high pressure switch that would run the fan at hgh speed, but it looks like the system reads the pressure though an analog sensor and the fan has PWM speed control.
I want to make the fan run at high speed to check the fan circuit and fan.
The pressure I have seen on the VCDS is about 18 BAR. and when the condensor is not getting cooling air needed this would be reasonable.
I think that the fan would run in high speed under these conditions.
Does anyone know how to check the fan with the VCDS?
Thanks,
JDB
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24 Posts
I have been looking deeper into the A/C problems with my 1009 Jetta TDI.
It seems that there is no high/low pressure switch on this model. There is a pressure sensor that is located in the same place (I think since I have not yet located it).
I have the Bently DVD ordered, but it is not yet here.
I think ..... that the computer looks at the analog signal to determine what fan speeds etc are necessary.
The pressures need to get pretty high for the fans to be sped up. I have looked at the pressures with gauges, but not a the same time I had the VCDS hooked up.
I have been looking for information on how the system works to little profit.
Since the car cools good when moving , but takes moving at a pretty good speed to start cooling. When it is cooling it works quite well.
I suspect that the fans are working as thay should, but are not being commanded to run fast enough.
Unlike the earlier cars I THINK that the signals are "analog" or PWM or digital via CANBUS.
I would like to know how to command high speed via VCDS. This would confirm that the fans are working properly.
I also need to look at the pressures via VCDS vs. the gauges to see if the sensor might be reading low or the charg is really too low to trigger the high speed operation of the fans.
This seems to be the problem---- The fans do not speed up when high head pressure would indicate insufficient cooling of the condenser coil.
Any ideas?
Thanks,
J.D.B.
It seems that there is no high/low pressure switch on this model. There is a pressure sensor that is located in the same place (I think since I have not yet located it).
I have the Bently DVD ordered, but it is not yet here.
I think ..... that the computer looks at the analog signal to determine what fan speeds etc are necessary.
The pressures need to get pretty high for the fans to be sped up. I have looked at the pressures with gauges, but not a the same time I had the VCDS hooked up.
I have been looking for information on how the system works to little profit.
Since the car cools good when moving , but takes moving at a pretty good speed to start cooling. When it is cooling it works quite well.
I suspect that the fans are working as thay should, but are not being commanded to run fast enough.
Unlike the earlier cars I THINK that the signals are "analog" or PWM or digital via CANBUS.
I would like to know how to command high speed via VCDS. This would confirm that the fans are working properly.
I also need to look at the pressures via VCDS vs. the gauges to see if the sensor might be reading low or the charg is really too low to trigger the high speed operation of the fans.
This seems to be the problem---- The fans do not speed up when high head pressure would indicate insufficient cooling of the condenser coil.
Any ideas?
Thanks,
J.D.B.
A/C compressor short cycle?
I have a 2000 Jetta that started growling a day ago.... I replaced the relay and A/C pressure switch a few months ago and had great A/C. First time in a couple of years that the A/C worked well! But just the other day, after slowing from highway speed and coming to a stop at the end of an off ramp, I could hear/feel the car growling. The A/C, while still blowing strong, got warmer and warmer, as soon as I started rolling again the air cooled back down....
I noticed the large fan on the radiator was not spinning and when I manually tried to spin it, it wouldn’t make a full revolution. I swapped it out from a donor car, but after a few minutes, the car started growling every couple of minutes, and when I checked the compressor, it seems to be short cycling in conjunction with the growling noise....
Any idea's on the issue? I'm thinking the coolant temp switch on radiator? Or is there another "switch" I need to check? Could the compressor be going out?...
I have a 2000 Jetta that started growling a day ago.... I replaced the relay and A/C pressure switch a few months ago and had great A/C. First time in a couple of years that the A/C worked well! But just the other day, after slowing from highway speed and coming to a stop at the end of an off ramp, I could hear/feel the car growling. The A/C, while still blowing strong, got warmer and warmer, as soon as I started rolling again the air cooled back down....
I noticed the large fan on the radiator was not spinning and when I manually tried to spin it, it wouldn’t make a full revolution. I swapped it out from a donor car, but after a few minutes, the car started growling every couple of minutes, and when I checked the compressor, it seems to be short cycling in conjunction with the growling noise....
Any idea's on the issue? I'm thinking the coolant temp switch on radiator? Or is there another "switch" I need to check? Could the compressor be going out?...
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I had exactly the same symptoms in my 2009 JSW yesterday. the JSW sat in the Texas sun all afternoon, and at 1700 (quitting time) it blew HOT air until I got off of Fort Sam (where the speed limit is 25mph).
It was as though it refused to work on-post...
Glad to hear it's not just me (this is normal, right?:ugh)
What several people have found out on our year models is that the RCV on the compressor goes bad. It basically controls the flow of freon through the compressor since it doesn't technically turn on and off. You can't buy it separate from VW but there is an aftermarket version made in china available that several people have had good results with. But you are looking at a $600 compressor vs a $45 RCV. So it is worth a shot. Many people have had good luck,including myself, with evacuating the freon, shooting an ounce or two into the system, and recharge. This will break loose some of the "gunk" that stops up the valve. Others have removed the valve and cleaned it. This was gonna be my next step if mine didn't work. I did have to use it several times before it "freed" up and now works every time. Before it would work, but you would just about start sweating because it took such a long time to come on.
Mine seems to have failed as well. It's a 2011 JSW with manual AC. The light goes on, but no cold air. Vent fan works fine and there are no blown fuses.
I'm going to bring it into the dealer tomorrow or Tues, and will report on what the fix was, but do you have a "decision tree" for this? ie. what sequence of events has to be in place for the system to work?
thx,
Dan
Mine didn't work because there was no refrigerant in the system. The dealer re-charged it and added dye. It's not yet evident where it's been leaking.
Dan
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11 Posts
Is the RCV valve serviceable w/out system recharge, ie - is it mounted in a schraeder valve? Thanks, Mike
When AC is selected the Fans are called & should operate. Check fuses.
Check connection to fans at front underneath car. If you have twin fans, the large one controls the smaller one. In this case both should operate.
there are many scenarios, i think most often the radiator condenser fans are not working properly, which in turn makes ac compressor cycle more often and the switch in the compressor breaks, so check your fans!! mine were not working took them out of car(ground dog ears off) took housing apart and the brushes for the fan motors were hung up causing the problem, i cleaned everything up and both fans now work as well as the ac
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