Check your radiator/condenser fan operation NOW

dremd

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Why? It won't be working any harder then if the main cooling fan were running.

Completely false.

Higher temperatures cause high side pressure to spike, ideally the fan control module detects the high pressure and shuts off the compressor, but with one fan it will probably just make the compressor work 2x as hard.
 

Rinderle_77

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Thanks to this thread being a Sticky, I discovered that the fans were both fried, before cooking the AC system, on the bargain beetle I just recently purchased. Saved me a pile of headaches! Replaced the fan assembly this afternoon (with a Chinese Ebay setup for $80). I guess I got what I paid for, as the RH condenser fan made it about 10 min before there was smoke coming out the hub....like the shaft is spinning inside the fan hub and melting the plastic. Yes, they both spun freely after install, and worked as they should in the test. Ebay seller is sending out a new (free replacement) set tomorrow, so hopefully it was just a freak happening.
It’s not the fan that dies. The low speed resistor in the fan is too small. Vw designed it wrong and nobody ever put a larger resistor to handle it.
This one was not the resistor. The fan mount on the cheap Chinese fan set, was weak; which allowed the running fan to come into contact with the shroud. This effectively friction welded the fan to the shroud and the shaft spun in the hub of the fan.

I replaced the fan and shroud set with another set that the seller sent me at no charge. They made it until last week...when the resistors cooked.

Any chance anyone has used these? Might be a good option as the resistors are outside the motor housing and where they can receive airflow from the running fan....

https://www.amazon.com/Condenser-Ra...=1532751830&sr=1-2-catcorr&keywords=1c0959455
 

acidtonic

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Heres one

Heres one I need help with...

I keep burning up AC clutches. First I changed the clutch with loud bearing failure but everything worked.

Second clutch lasted about a week. One long drive and it was toast. Coil failed (due to heat I believe) and had infinite resistance.

This time I replaced the entire compressor with a new unit that had a new coil/clutch preinstalled. Filled 28g by weight all was well. Lowside low 30s, highside 200-230s if anyone is curious.

One long drive over an hour on a 90 degree day and it started blowing warm air. Got out and looked and the new clutch was slipping and had a ring of heat-discoloration. Caught it in time and after cooldown the clutch still engages but I am afraid to run it before fixing the root cause.

Do I need to replace the fcm or the high pressure sensor next? I tested the voltage without load and receive 9.6 at the plug going to the coil. Both radiator fans run fine and strong. Fuses are fine and not melted.

Observations are the ac doesnt cycle when parked but under heavier loads it feels like it cuts off and on but i thought that the ecu normally shut off the clutch under high loads (i.e. WOT). Seems like its not grabbing as hard as it could and longer drives are causing too much heat.

Any ideas? Was going to replace the FCM and high pressure sensor next.
 

SilverGhost

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Uh, did you check to see if the new compressor already had oil in it? The ones we install have full system charge already. Unless you flushed the system there was still oil remaining. 28g of oil or Freon? Normally takes 700g Freon on a MkIV.

First thought I had was to verify the air gap on the clutch. Then check the force required to turn the compressor. Also check the wiring to the clutch while you are there - if full current is not reaching the clutch then the coil can't pull tight enough and it slips.

WOW! 230PSI?! I'm seeing low 30s low side and 150-180 high side. Unless it has been running a while in 94F+ and high humidity weather. Even then I rarely see 200+ high side. BTW - I spent 7 years in Florida, never saw that unless something was broken/restricted.

Our cars don't cycle the compressor clutch. They are variable displacement and don't cycle unless pressure limit is reached or you turn AC off.

Sorry about the random burps of info,

Jason
 

acidtonic

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03 TDI
I did fill the compressor with pag oil prior to install. I think I meant to say oz instead of g. We looked it up when i bought the freon and i did indeed refill this on a nearly 100 degree day that was rather humid. Pulled vacuum to purge before filling as is recommended.

I think the voltage is too low at the plug. But i need another weekend to get under and test it again. I wasn't hitting over pressure so I'm now thinking that the high-pressure AC sensor is indeed the cause of my cycling. That and the voltage means I probably have multiple issues going on.
 

SilverGhost

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So you filled compressor with PAG oil, but was there any oil already in the compressor when you bought it?

230 PSI is still a bit too high, IMHO.

Question on the high pressure sensor - is it not reading? Why do you think it's the cause of the cycling? If its a 3 wire sensor then it "talks" to FCM and it sends actual pressure, not just a switch that closes at a high or low limit. Most common failure is leaking out the sensor or just total failure which would mean no AC at all.

I think you may have a couple issues. A possible mechanical issue causing too high of pressure and electrical supply to clutch. But this is all Internet diag, so....

Jason
 

Rinderle_77

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This one was not the resistor. The fan mount on the cheap Chinese fan set, was weak; which allowed the running fan to come into contact with the shroud. This effectively friction welded the fan to the shroud and the shaft spun in the hub of the fan.
I replaced the fan and shroud set with another set that the seller sent me at no charge. They made it until last week...when the resistors cooked.
Any chance anyone has used these? Might be a good option as the resistors are outside the motor housing and where they can receive airflow from the running fan....
https://www.amazon.com/Condenser-Ra...=1532751830&sr=1-2-catcorr&keywords=1c0959455
Update: I ordered these fans, they came in as a standard set of fans with enclosed resistors. :mad: Also, the small (passenger side) fan motor protrudes ~1.5" past the mount spider which will allow it to come into contact with the line off the back of the AC compressor. :(

Emailed the company with my concerns. They replied that the fans I was after are out of stock, and not sure when they'll be back in stock. Therefore, they have sent a return shipping label and will refund....

At this point, I wish I could just wire in a relay using the low speed power for trigger to send power to the high speed side of the fans and just run them on high speed any time the low speed is called for. I'm just not sure what that would back-feed on the high speed side of the FCM, etc.
 

BobnOH

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central Ohio
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Update: I ordered these fans, they came in as a standard set of fans with enclosed resistors. :mad: Also, the small (passenger side) fan motor protrudes ~1.5" past the mount spider which will allow it to come into contact with the line off the back of the AC compressor. :(

Emailed the company with my concerns. They replied that the fans I was after are out of stock, and not sure when they'll be back in stock. Therefore, they have sent a return shipping label and will refund....

At this point, I wish I could just wire in a relay using the low speed power for trigger to send power to the high speed side of the fans and just run them on high speed any time the low speed is called for. I'm just not sure what that would back-feed on the high speed side of the FCM, etc.
Surprised you even got that far with Amazong, often they won't divulge 3rd party sources.
You should be able to rig the fans to operate that way, you'll need to "engineer" the new configuration to provide proper current where needed. Electrics are a bit more than just connecting wire, you may need a resister, capacitor or some such a thing. You may even need to change conductor size. Normally it's easier to just fix it as designed.
 

Rinderle_77

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Surprised you even got that far with Amazong, often they won't divulge 3rd party sources.
You should be able to rig the fans to operate that way, you'll need to "engineer" the new configuration to provide proper current where needed. Electrics are a bit more than just connecting wire, you may need a resister, capacitor or some such a thing. You may even need to change conductor size. Normally it's easier to just fix it as designed.
Yeah, I was surprised to get this far... As far as wiring in the relay, I get by ok with most minor electrical repairs, but I'm like you in thinking that there would have to be a diode or two in there somewhere. I just hate the idea of tearing apart brand new fans to remove/relocate the resistors and effectively throw away what "warranty" they might have.....

Maybe Dan will chime in with yet another bit of wisdom. Like I said before, I know there has to be a way to make the fans only run on high as if the low speed wiring and resistors aren't even there.

And yes, I did look into the PWM controller from the fellows across the pond, you still have to have functional low speed fan motors (including the resistors) for the controller to work. It just manipulates the voltages and signal to alleviate stresses of constant load on the resistors.
 

The4ork

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Hi folks. 2012 Jetta issue.

I was having intermittent cooling fan operation, noticed by my a/c kicking on and off in city driving/red lights.

So i replaced the main large fan with new. seemed to work flawless for a day (probably coicidence) and im right back where i started.

I thought maybe i didnt connect the main electrical connector all the way so i jacked the car, pulled the lower cover off and right before i stuck my hand on the connector my fans randomly kicked on for the after-run function. I thought that was very odd.

Perhaps its the a/c pressure switch? as in the pressure had changed while it sat for 10 or so minutes while i was jacking the car and removing the cover?

any help would be greatly appreciated. I dont have a vag com and plan on getting some help later today but its not a guarantee i'll be able to do it.
 

BobnOH

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Yea, Dan's been out since December. Hope he's O.K. I know he does take some long vacations.
I can tell you he's answered about every question imaginable on things AC. Do some advanced searching, include the term DanG144 and of course your issues.
VW TDI Search Engine
 

The4ork

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There is just so much to go through, it would take me hours! I just really do not understand why this NEW damn fan isnt coming on, so its gotta be non-fan related. And on such a newer car.... i mean its 6 years old now. Frustrating since its not even paid off before its starting to go to ****. I expect this kind of crap on my 03....
 

BobnOH

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Starting with Post#1, Dan covers fan diagnosis complete. Not sure what's different for 2012. But a quick read says adequate refrigerant pressure and proper signal from the high pressure sensor.
There is just so much to go through, it would take me hours...........................
You can trim that down to minutes using advanced search. Must be frustrating on such a new car!
 

The4ork

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So I found my new fan must not have seated in the main plug all the way. I got a nice little burn spot around the pin for the ground. In fact the new mk6 plug is a terrible design. After a few years in the heat it won't hold together at all any more. It's just held together by friction. Tab is in tact but barely has a grab. Will zip tie.

Hope it was just burning from being loose and not any other problem.

Also, my fan will go from low to high and back to low... But my ac will also only get to 60 degrees, and when the fan goes to low it will only go to 65 degrees. This is sitting in the driveway and it's currently 100 degrees outside. I feel like it should be blowing colder.
 

The4ork

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Can't figure out how to post pics from my phone and Photobucket doesn't work anymore but the connector is burning up at the large ground pin.

I'm at a loss of what to do next. I'm starting to hate this car. What a ****ty engineered plug.
 

tom2turbo

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Checking A/C Cooling fans for operation as directed by DanG144 on #1. Diagnostics show left fan inoperative high and low speed. Disassembled old fan which suffered from the apparent epidemic melting brush holders and ceased functioning. I do not know how long this situation has been occurring.
Ordered new Behr fan from FCP.com, a long term supplier of mine in the Volvo world.

Thanks Dan!
 
Last edited:

SilverGhost

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Hi folks. 2012 Jetta issue.
I was having intermittent cooling fan operation, noticed by my a/c kicking on and off in city driving/red lights.
So i replaced the main large fan with new. seemed to work flawless for a day (probably coicidence) and im right back where i started.
I thought maybe i didnt connect the main electrical connector all the way so i jacked the car, pulled the lower cover off and right before i stuck my hand on the connector my fans randomly kicked on for the after-run function. I thought that was very odd.
Perhaps its the a/c pressure switch? as in the pressure had changed while it sat for 10 or so minutes while i was jacking the car and removing the cover?
any help would be greatly appreciated. I dont have a vag com and plan on getting some help later today but its not a guarantee i'll be able to do it.
Fans on 2012 Jetta (from ElsaPro);

Fan control module is built into large fan. It receives a data signal from ECM. Fan will default to 100% if powered up and missing communication with ECM. There is no set "high" or "low" speed - is is commanded a percentage between 0% and 100% depending on load.

And that warning on your radiator support "Fans may start at any time" goes along with the TSB that with TDI engines fans may run up to 16 minutes after car is shut off.

Sounds like you may have taken trouble shooting from the wrong type of car. BTW, I always remind people that both fans always run together. If only one fan is running there is a problem. This system will record DTCs in ECM if there is fault with the fans (bad enough is notices).

Jason
 

wonneber

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Can't figure out how to post pics from my phone and Photobucket doesn't work anymore but the connector is burning up at the large ground pin.
I'm at a loss of what to do next. I'm starting to hate this car. What a ****ty engineered plug.
I'm thinking you may have a fan drawing to much power or a bad ground back feeding through the circuit.

Check the amperage each fan is drawing. Both should be about the same.

Check the ground connection on the left side of the fans.

Long shot, the body ground under the battery tray is the one going back to the battery. If it's bad anything that grounds to the body is bad.
 

tom2turbo

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2004 Jetta TDI Wagon
Checking A/C Cooling fans for operation as directed by DanG144 on #1. Diagnostics show left fan inoperative high and low speed. Disassembled old fan which suffered from the apparent epidemic melting brush holders and ceased functioning. I do not know how long this situation has been occurring.
Ordered new Behr fan from FCP.com, a long term supplier of mine in the Volvo world.

Thanks Dan!

Ordered new right OEM fan from Pelican parts known from my Porsche days. The old one was "gunked up" and I figured to replace all the wear parts at once.

Installed left Behr and right OEM VW fans. Both fans now run with A/C turned on. Just in time for late summer trips.
 

Vwdummy

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2004 Jetta
Info here in another thread but this one may be better suited a/c gurus please read

Old Yesterday, 01:24 #1
Vwdummy
Newbie
Help with puzzling heat issue 04 Jetta 2.0 gasser.
Hopefully someone can steer me in the right direction here.
About a month ago my daughter reported a burning smell. After looking into things I noticed the serpentine belt distorted and idler pulley partially melted. The A/C clutch had also failed and the plastic winding covering for the clutch was also partially melted.
Fast forward a bit after replacing a/c clutch due to a locked up bearing, tensioner and serpentine belt it looks like the same thing is happening again. When I replaced those items everyone was happy and everything worked properly. Had no noises, cold a/c ect.
What could cause that kind of heat buildup when all bearings now spin freely? Both cooling fans were verified to operate both in low and high speeds, all fluid levels are adequate and compressor, alternator and ps pump spin freely.
Within 100 miles or so the tensioner pulley has grooves melted into from the belt ( it started out smooth) and belt shows signs of excessive heat as well.
I am hoping someone on here has had a similar issue. Other forums I looked at didn't really have anything on this specifically. All the basics have been checked repeatedly and look normal. The car has roughly 189,000 miles but still runs great other than this new issue.
One more note to throw in there, I had replaced a/c clutch roughly 2 years ago and had no issues at all after that replacement.
I hate to give up on this one but melted serp belts and pulleys aren't making me warm and fuzzy.
Thanks in advance for any help you folks can provide
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Old Yesterday, 04:16 #2
oilhammer
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The compressor is probably failing. I'd recover and evacuate the system, take the high side line off at the condenser coming from the compressor and look to see if there is any gray film or grit in there.
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Old Yesterday, 18:49 #3
WildChild80
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If you turn off the AC does it still melt the belt? Are the replacement parts cheap parts?

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Old Today, 02:36 #4
Vwdummy
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In process of figuring out if it happens without a/c now. I removed the drive disk for the compressor from the a/c clutch completely so there would be no chance of engaging. These are simple enough to remove on this car so figured why not. The new bearing for the pulley has already gotten wounded from the excess heat. It still turns free enough to run for testing but will need replaced again. I let the car run for about 45 minutes at idle and it didn't see anything out of the ordinary with the belt.
What I did notice was either the thermostat is not opening, or the radiator may be clogged because top rad hose was hot and the bottom cool to the touch. Temp guage showed just above 190. Still need to verify water pump. So now I'm wondering if this could be a cooling issue?
Another thing I thought was strange was both fans run as soon as car is started. The large will turn off after a couple of minutes but the small stays running as long as car is running and doesn't shut off until a few minutes after engine is turned off. That seems normal IF a/c is running but not when a/c is off.
Could this be causing discharge pressure from a/c to be too high creating the excess heat? If refrigerant can't convert back into liquid wouldn't it get extremely hot and possibly cause these issues?
Let me know if I'm way off base here please.
 

Genesis

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What I did notice was either the thermostat is not opening, or the radiator may be clogged because top rad hose was hot and the bottom cool to the touch. Temp guage showed just above 190. Still need to verify water pump. So now I'm wondering if this could be a cooling issue?
Nope -- normal. The thermostat *regulates* coolant flow; at idle and no load a diesel doesn't produce much waste heat (thus the reason you have ZERO heat in the cabin in the winter when idling for a long time!)
 

SilverGhost

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Here is a thought - if the belt tensioner is not holding correct tension on the belt, then enough load from AC compressor and/or alternator could cause belt to slip. And don't forget PS pump is on that belt as well.

Also, radiator fans are hardwired as pair. There is no reason EVER for one to run without the other.

Jason
 

Vwdummy

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Thanks for the input gentlemen. Just for clarity the tensioner and belt were both replaced with the ac clutch.
Did some more digging on this. Cooling system all checks out. No clogged radiator, replaced thermostat while I had system drained to check rad and the water pump looks and feels to be in good shape.
Both cooling fans work in low and high speed. Ended up removing ac clutch pulley completely and installed belt for non ac car. Fired it up and everybody seems happy. No jerking at all on tensioner and belt running very smooth.
As I understand it on a 2004 gasser the fans rarely run at all without ac on. If temp gets up there the large fan only will come on at first. If extra cooling needed the small one will cycle as well. This is the way these fans have always acted in the past. Is this not correct? It remains to be seen if the car stays happy without the ac system hooked up.
What is is looking like now is a clog somewhere in the ac system. Compressor spins freely by hand but like I said earlier it gets hot enough to melt clutch bearing seals, idler pulley ect.
Can anyone tell me if there is a high pressure cut off on these cars? It seems odd that the pressure could get high enough to generate enough heat to destroy things and not shut down the ac.
Would also like to know what conditions turn small fan on. Is there a pressure switch for it in the ac circuit?
Right now when car is started both fans come on as if ac is turned on when it is not. After a minute or so the large will turn off because engine not up to temp. The condenser fan runs the entire time the car is running and does not shut off until about 10 minutes after car is turned off. It seems as though a pressure or temp switch is stuck telling the condenser fan to run.
Could that behavior be a result of a blocked ac high pressure line?
If I replace compressor should I replace everything else as well. I know the rec/dryer should be replaced but what about condenser and expansion valve?
Kind of worried that whatever I don't replace is where the blockage would be and I will be right back in the same boat.
Someone help me make some sense out of this madness please.
By the way ambient temperature on surgery day was roughly 90F
 

SilverGhost

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Thanks for the input gentlemen. Just for clarity the tensioner and belt were both replaced with the ac clutch.
Did some more digging on this. Cooling system all checks out. No clogged radiator, replaced thermostat while I had system drained to check rad and the water pump looks and feels to be in good shape.
Both cooling fans work in low and high speed. Ended up removing ac clutch pulley completely and installed belt for non ac car. Fired it up and everybody seems happy. No jerking at all on tensioner and belt running very smooth.
As I understand it on a 2004 gasser the fans rarely run at all without ac on. If temp gets up there the large fan only will come on at first. If extra cooling needed the small one will cycle as well. This is the way these fans have always acted in the past. Is this not correct? It remains to be seen if the car stays happy without the ac system hooked up.
What is is looking like now is a clog somewhere in the ac system. Compressor spins freely by hand but like I said earlier it gets hot enough to melt clutch bearing seals, idler pulley ect.
Can anyone tell me if there is a high pressure cut off on these cars? It seems odd that the pressure could get high enough to generate enough heat to destroy things and not shut down the ac.
Would also like to know what conditions turn small fan on. Is there a pressure switch for it in the ac circuit?
Right now when car is started both fans come on as if ac is turned on when it is not. After a minute or so the large will turn off because engine not up to temp. The condenser fan runs the entire time the car is running and does not shut off until about 10 minutes after car is turned off. It seems as though a pressure or temp switch is stuck telling the condenser fan to run.
Could that behavior be a result of a blocked ac high pressure line?
If I replace compressor should I replace everything else as well. I know the rec/dryer should be replaced but what about condenser and expansion valve?
Kind of worried that whatever I don't replace is where the blockage would be and I will be right back in the same boat.
Someone help me make some sense out of this madness please.
By the way ambient temperature on surgery day was roughly 90F
Again, see my earlier post, in reference to the highlighted parts of your post.

SilverGhost said:
Also, radiator fans are hardwired as pair. There is no reason EVER for one to run without the other.
I have an idea - load in the failing compressor could be causing repeated failure of the clutch. Possible the pressure control valve is sticking and forcing the compressor to higher loads than it should. Also the heat load is (by your description of the failure) limited to the clutch area of the compressor. Cooling system failure would have lead to other parts on the car failing first. Also I would believe blockage in the the Freon system would have resulted in noticeable AC performance problems.

Jason

PS, if you have fans coming on one at a time then you should look into why. THAT IS NOT NORMAL.
 

gojo71

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ac system not working

Now is the time of the year to check that your pair of electric fans that provide cooling for both the radiator and air conditioner condensor are functioning. Do not needlessly age your Air Conditioning compressor by running it at too high a pressure and temperature.
(Now being spring, with temperatures above 35 F. There are interlocks that prevent operation below freezing.)
A4's and A5's (I suspect others, too) have bad problems with radiator/condensor coolant fans not being operational.
There is no DTC or MIL light that comes on for this. No overt warning at all.
Most people do not notice anything until both of their fans have quit completely, and then they might notice that the AC compressor kicks off when at stop lights or in traffic. They may notice their AC is not as cool as normal. This is the terminal stage of this disease.
Here is the usual progression of this failure.
1)One fan slow speed operation fails, no one notices. The AC is operating at higher than normal temps and pressures, but still does a good job.
2) The second fan's slow speed operating mode quits; no one notices. The AC compressor is running even hotter and at higher pressures. When the vehicle is not moving, the pressure builds up to the high pressure point on the refrigerant pressure sensor. The high speed fans kick on, and the compressor kicks off; this lasts about 20 seconds, then the compressor kicks on and the fans kick off (they should be in slow, but that has failed. The cycle repeats about once per minute. Most people will still not notice this, as the refrigerant pressure stays high and they get some cooling.
3) The repeated cycling of the high speed fans, and their very high starting current will eventually cause some electrical connection or component to fail in the fan circuit. All fan operation is lost. This folks usually notice when they are at stop lights or in traffic, as the AC compressor will kick off and on repeatedly. Cabin cooling is usually affected, and many notice, but some think it is normal operation.
To avoid this scenario check your fan operation every time you check under the hood (every refueling, right?)
Manual AC (as opposed to Climatronic AC or Climatic AC -the transmission type is immaterial) cars, push the AC button in, place a fan in slow and leave your key to ON (engine does not have to be running). Both fans should run in slow (unless it is near freezing or your refrigerant pressure is too low.) If your AC light does not come on and your cabin fan does not work, do not proceed until you have troubleshot and fixed this problem; this is the primary signal to turn on the AC system.
Climatronic or Climatic AC cars (includes all A5 cars), with the engine running, select low cabin temperatures for climatronic or AC on fan on for Climatic, make sure you are not in ECON mode, and check your fans. Both should be running at a slow speed condition within about 30 seconds (they are infinitely variable in speed.) Again this is dependent upon not being in near freezing conditions and having adequate refrigerant pressure. Your fans key off of refrigerant pressure signals, so the compressor must be good and be loaded in order for the fans to see a high enough pressure to start.
During the engine output tests with VCDS, if there is a fan test (and there is on BEWs and BRMS) then BOTH fans should run together.
AC troubleshooting:Folks, a reminder. This thread is for solving electrical control problems in the Mk IV Air conditioning systems. If your clutch is engaging, and your fans are running, then you will not find your answer in this thread.
If your clutch is engaging and your fans are running, check out the Refrigerant Control Valve threads and the lost-foam-on-the-temperature-control dampers or flaps or doors threads. If your pressures are normal, look at the flapper doors, if the differential pressure is lower than it should be, then look at the RCV threads.
Some links to PDF papers on troubleshooting A4 fans and Manual Air conditioners. Please forward any questions or corrections to me (DanG144).
A4 fan troubleshooting
Sept 98 - May 99 Build date A4 Manual Air Conditioner Troubleshooting
Rev 7 May 99-end of A4 Manual Air Conditioner Troubleshooting.
Fan Repair
pinout of J293 Thanks to wulee
Refrigerant Pressure table vs temperature and G65 pressure transducer This is based solely on reading one (my own) pressure transducer; this is not guaranteed accurate. If you have the real calibration data, or data from your own transducer, please forward it to me.
A very kind anonymous user has generated a set of schematics for the MK IV (May99 to MY2005.) The first is one piece for easy viewing, the second is two pieces for easy printing. Thank you Anonymous.
http://pics.tdiclub.com/showphoto.php?photo=119224&title=view-ac-schematic&cat=517
http://pics.tdiclub.com/showphoto.php?photo=119223&title=air-conditioning-schematic-fans-and-ac-mk-iv&cat=517
This post was a life saver for AC system not working. Turned out it was Fuse on Battery for radiator fan/AC Comopressor..
Thanks for your complete explanation.
 

dloomis

Veteran Member
Joined
Oct 10, 2000
Location
Raleigh, NC
TDI
2000 Jetta TDI, manual (sold); 2005 New Beetle TDI, DSG
Just checked the two fans on my 2005 NB which I bought 2nd hand a few years ago. Both fans do NOT run at low speed using the initial test as indicated by OP. All fuses appear to be fine, but I got stuck at the radiator fan temperature switch plug test (jumping the red and red/white wires) to see if they run at slow speeds.

Does anyone have any tricks to getting this !@#$ plug off? The release clip is in an awkward spot and for the life of me I can't get it off. I absolutely hate these VW clips!!!
 

flash52

Well-known member
Joined
Jul 21, 2017
Location
Texas
TDI
2004 Beetle 1.9 BEH
Thanks to DanG, His A/C troubleshooting guide and personal help
2004 Beetle Bew
A/C quit working and before I could troubleshoot Timing belt failed

Got replacement Engine installed and started troubleshooting A/C
Did Dan's troubleshooting and only fail was pin T14/3

This pin keeps the compressor clutch off until 2500 rpm under max acceleration

so something in the ecm was telling the fcm I was max acceleration, so after talking to Dan I cut the wire about 6 inches feom fcm and all was good
Much cheaper fix than the ecm
So big thanks to Dan for all his help
Russell
 

kball

Well-known member
Joined
Nov 7, 2011
Location
BC
TDI
2006 mk5 tdi, 03 alh
04 bew running out of ideas

So my latest purchase is an 04 bew and now I noticed the AC doesn’t work.

Took it to a friends shop and had the AC drained and filled back to 800g. It was full to begin with. I followed the write up I found on here and here’s what I’ve got. Looks like 2 issues.
1-Key on engine off the fans won’t run.
2-AC clutch won’t engage with 12vdc applied to connector. Resistance is 4ohms which is in spec from what I’ve read.

1-Key on engine off the fans won’t run. They will spin for a few seconds occasionally.
I jumped the coolant temp sw connector in the rad, both hi and low speeds run both fans and that function is normal.
2-I can start both fans using the fan test with a vag cable.
Checked dash and Underhood Fuses are all good, swapped out fan module and pressure transducer from a known good car and no change.
3-When I applied 12v to the ac comp clutch it does nothing so that’s a separate issue since my fans won’t run even before the car is started.
4-The fact that I’ve turned the key on during testing and seen the fans coming to a stop by the time I get to the front of the car makes me think there’s some sort of power supply or ground issue. But if I try it again immediately they won’t budge.

Any insight is appreciated!
 
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