www.tdiclub.com

Economy - Longevity - Performance
The #1 Source of TDI Information on the Web!
Forums Articles Links Meets
Orders TDI Club Cards TDIFest 2016 Gone, but not forgotten VAG-Com List Unit Conversions TDIClub Chat Thank You




Go Back   TDIClub Forums > TDI Model Specific Discussions Areas > VW MKIV-A4 TDIs (VE and PD)

VW MKIV-A4 TDIs (VE and PD) This is a general discussion about A4/MkIV Jetta (99.5-~2005), Golf(99.5-2006), and New Beetle(98-2006). Both VE and PD engines are covered here.

Reply
 
Thread Tools
Old August 12th, 2018, 22:38   #1846
tom2turbo
Member
 
Join Date: Feb 2016
Location: Portland
Default

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 by tom2turbo; August 12th, 2018 at 22:40.
tom2turbo is offline   Reply With Quote
Old August 13th, 2018, 07:29   #1847
SilverGhost
Veteran Member
 
SilverGhost's Avatar
 
Join Date: Mar 2005
Location: Old Hickory, TN. Settling here...
Default

Quote:
Originally Posted by The4ork View Post
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
SilverGhost is offline   Reply With Quote
Old August 18th, 2018, 20:29   #1848
wonneber
Veteran Member
 
Join Date: Oct 2011
Location: Monroe, NY, USA
Default

Quote:
Originally Posted by The4ork View Post
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.
wonneber is offline   Reply With Quote
Old August 24th, 2018, 18:37   #1849
tom2turbo
Member
 
Join Date: Feb 2016
Location: Portland
Default

Quote:
Originally Posted by tom2turbo View Post
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.
tom2turbo is offline   Reply With Quote
Old August 30th, 2018, 19:28   #1850
Vwdummy
Newbie
 
Join Date: Aug 2018
Location: Pa
TDI(s): 2004 Jetta
Default 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
Vwdummy is offline Reply With Quote

Old Yesterday, 04:16 #2
oilhammer
Certified Volkswagen Nut Vendor

oilhammer's Avatar

Join Date: Dec 2001
Location: St Louis
TDI(s): There are just too many to list....
Fuel Economy: fantastic
Default
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.
__________________
oilhammer
www.cardocautomotive.com
oilhammer is online now Reply With Quote
Old Yesterday, 18:49 #3
WildChild80
Veteran Member

Join Date: May 2016
Location: Hampton Roads, VA
TDI(s): 2001 Jetta TDI 2000 Jetta TDI 2000 New Beetle TDI ALL 5 speeds
Fuel Economy: 50ish
Default
If you turn off the AC does it still melt the belt? Are the replacement parts cheap parts?

Sent from my Pixel XL using Tapatalk
WildChild80 is offline Reply With Quote
Old Today, 02:36 #4
Vwdummy
Newbie

Join Date: Aug 2018
Location: Pa
TDI(s): 2004 Jetta
Default
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.
Vwdummy is offline   Reply With Quote
Old September 3rd, 2018, 14:17   #1851
Genesis
Veteran Member
 
Join Date: Feb 2003
Location: Niceville, FL
Fuel Economy: 53/48/42
Default

Quote:
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!)
Genesis is online now   Reply With Quote
Old September 4th, 2018, 08:35   #1852
SilverGhost
Veteran Member
 
SilverGhost's Avatar
 
Join Date: Mar 2005
Location: Old Hickory, TN. Settling here...
Default

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
SilverGhost is offline   Reply With Quote
Old September 5th, 2018, 14:57   #1853
Vwdummy
Newbie
 
Join Date: Aug 2018
Location: Pa
TDI(s): 2004 Jetta
Default

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
Vwdummy is offline   Reply With Quote
Old September 6th, 2018, 07:12   #1854
SilverGhost
Veteran Member
 
SilverGhost's Avatar
 
Join Date: Mar 2005
Location: Old Hickory, TN. Settling here...
Default

Quote:
Originally Posted by Vwdummy View Post
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.

Quote:
Originally Posted by SilverGhost
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.
SilverGhost is offline   Reply With Quote
Old September 8th, 2018, 06:46   #1855
gojo71
Newbie
 
Join Date: Jun 2015
Location: Cincinnati, Ohio
TDI(s): 2003 Golf
Fuel Economy: 45MPG AVG
Default ac system not working

Quote:
Originally Posted by DanG144 View Post
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.ph...ematic&cat=517
http://pics.tdiclub.com/showphoto.ph...-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.
gojo71 is offline   Reply With Quote
Reply


Currently Active Users Viewing This Thread: 2 (0 members and 2 guests)
 
Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -7. The time now is 14:37.


Powered by vBulletin® Version 3.8.5
Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.
Copyright - TDIClub Online LTD - 2017
Contact Us | Privacy Statement | Forum Rules | Disclaimer
TDIClub Online Ltd (TDIClub.com) is not affiliated with the VWoA or VWAG and is supported by contributions from viewers like you.
1996 - 2017, All Rights Reserved
Page generated in 0.23407 seconds with 11 queries
[Output: 114.33 Kb. compressed to 100.07 Kb. by saving 14.26 Kb. (12.47%)]