Check your radiator/condenser fan operation NOW

jun_1.8T

Member
Joined
May 31, 2009
Location
GTA, Ontario
TDI
Jetta
ok guys....my buddy who has a 2002 Jetta 1.8T just told me that he has been having the same problem as me. it should be the same a/c system right??? just want to make sure first before i tell him how to test his fans.

thanks!
 

CaptainKirk

Veteran Member
Joined
Jul 8, 2005
Location
Kalamazoo, MI
TDI
Jetta, 2002, Black
97 Passat AHU 2002 Jetta ALH

Dan

Thanks for this post. I have two vehicles that have the same problem

The low pressure valve is leaking (on the fat line), it hisses when you take off the protective cap. You can charge it, but it only holds a charge for about a month.

On the 97 Passat are you able to repair/replace the valve or do you have to replace the whole line? The ETKA shows a part number 3A1820741D for the line and 357820795J for just the valve. It seems my experience the on another car, when you went to unscrew the valve, it twisted right off the line and I had to replace it. Maybe there's a special way or tool needed to remove the valve?

Basicall the same question on the 2002 Jetta, can you repair/replace just the valve or do you have to replace the whole line?
 

DanG144

Top Post Dawg
Joined
Aug 2, 2007
Location
Chapin, South Carolina, USA
TDI
2005 A4 Jetta 5spd
Folks,
My experience is fairly limited. I can do fairly well on the electronics, and controls.

On the mechanical side, I am fairly ignorant.

I have removed schrader type valves on other systems and have not had a problem. It was essentially like removing a bike valve core.

Having someone bleed the system (remove the charge) slowly down to atmospheric pressure before trying to remove the valve is advisable.

Dan
 

VegBug

Veteran Member
Joined
Apr 30, 2007
Location
Indianapolis
TDI
'98 New Beetle
Ok, need a little help here. Where exactly is the compressor on a 98 NB?! Would someone happen to have a diagram or picture where this think is located? Darn engine bay is so tight I can't see much of anything!

Replaced the battery fuse box with new fuses from a 02 Jetta be parted out by a friend. Getting stronger blowing from fans and a mild cool feeling but not a strong cold. Checked all related fuses in cabin as well. Going to try and check G65 later today but man it's a stinker to get to!!

Thanks

Jerry
 
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jun_1.8T

Member
Joined
May 31, 2009
Location
GTA, Ontario
TDI
Jetta
ok....i got confused there with the pins for the thermoswitch. i have confirmed today that i have 12 volts coming out of my pin#2 for the thermo switch harness. did the test but still no fans came on for both slow and fast speed. took the car for a drive and only the drivers side fan works when i turn on my a/c. the car would still overheat when i let it idle and no fans work during this point. so...my fan should be ok as it runs sometimes right??? could it be my FCM that is bad??? i would still try to power up my fans straight from the battery to completely rule out my fans.

one question....should both fans come on at the same time eventhough im not using my a/c??? and if ever my FCM is bad...should it cause my fans to not run on slow speed???

thanks!
 

DanG144

Top Post Dawg
Joined
Aug 2, 2007
Location
Chapin, South Carolina, USA
TDI
2005 A4 Jetta 5spd
jun_1.8T said:
ok....i got confused there with the pins for the thermoswitch. i have confirmed today that i have 12 volts coming out of my pin#2 for the thermo switch harness. did the test but still no fans came on for both slow and fast speed. took the car for a drive and only the drivers side fan works when i turn on my a/c. the car would still overheat when i let it idle and no fans work during this point. so...my fan should be ok as it runs sometimes right??? could it be my FCM that is bad??? i would still try to power up my fans straight from the battery to completely rule out my fans.

one question....should both fans come on at the same time eventhough im not using my a/c??? and if ever my FCM is bad...should it cause my fans to not run on slow speed???

thanks!
Go ahead and test the fans directly putting power to them.

It sounds to me as if the most likely scenario is two bad fans.

They should never run singly, NEVER RUN SINGLY, both should always run together.

The most likely scenario is that one fan is getting enough power through the stuck brushes to run when the vibration from the running engine, and it has the 14.4 volts instead of 12.5 volts, but not in the low voltage, no vibration scenario.

The fact that one low speed fan does come on with your AC indicates it is likely that your Fan Control Module is working. In this condition they are both started by the same relay inside the FCM.

The slow speed fans can be started from the thermoswitch, even with the key off, totally independent from the fan control module.

The fan control module is used for all the start conditions except the radiator fan thermoswitch in low speed.

Fast speed requests from the thermoswitch, the ECU high temperature, or the Air Conditiioner high pressure all require a functional Fan Control Module. ALL FAST SPEED OPERATION REQUIRES A FUNCTIONAL FAN CONTROL MODULE.

If you were at my place we would directly test the fans, expecting one to certainly not run, the other to probably not run. Even if they both ran, based on what you have told me, I would probably clean the brush holders on both of them.

Dan
 

rcnaylor

Veteran Member
Joined
Feb 28, 2006
Location
Amarillo, TX
TDI
2014 Jetta Sportswagen Silver
OK, my driver side fan isn't coming on.

I'm not a mechanic. Has anyone had one of these fixed? If so, how much?

Do they just put in new (how much)?

I might be able to do a little repair, if the sucker is really high to get fixed or replaced.

Pain v. cash you know. ;(
 

DanG144

Top Post Dawg
Joined
Aug 2, 2007
Location
Chapin, South Carolina, USA
TDI
2005 A4 Jetta 5spd
I do not think it would pay to have any mechanic or shop fix the fan for you, due to the labor costs.

Fixing it yourself would cost a dremel tool and cutoff wheel, JBKwik Weld, maybe some emory cloth and degreaser to clean the spots to put the JBWeld back on, and a spray can of brake cleaner or no-residue electrical contact cleaner. This assumes it is repairable. If it does not spin easily then it is probably not repairable. If it spins easily then you have about an 80% chance that it is repairable (cleaning the brush holders.) The directions are in the first post, link near the bottom.

A fan off of E-bay costs $80 or so for an A4. To put it in takes putting the car up on ramps, removing the belly pan, unbolting three 27 Torx screws, and taking off one electrical connector. Then reversing the process. About 2 hours for the first timer.

Check with your dealer for his price. One story related to me was that the dealer would only replace the fan assembly (two fans and the shroud) for about $475 for parts and $200 for labor. But check with your dealer.

I would appreciate it if you posted what you learned here. You know how misleading second hand stories can be.
 

jun_1.8T

Member
Joined
May 31, 2009
Location
GTA, Ontario
TDI
Jetta
hi dan,

i did test the two fans by connecting them directly to my battery. both fans worked great with no problems on both speeds. so could it be my FCM then??? does the thermo switch connects straight to the fan or it goes through the FCM still??? because i tried jumping the thermo switch harness again and neither of the fans worked. so im guessing there is a fault in the FCM....could it be possible???

thanks for all the help.
 

rcnaylor

Veteran Member
Joined
Feb 28, 2006
Location
Amarillo, TX
TDI
2014 Jetta Sportswagen Silver
Thanks Dan. Helpful info and the thread may turn out to be a big saver if that fan being out would have cost me a compressor.

I'll try to post any useful info I run across in getting it fixed.
 

DanG144

Top Post Dawg
Joined
Aug 2, 2007
Location
Chapin, South Carolina, USA
TDI
2005 A4 Jetta 5spd
The thermoswitch does not go through the FCM for slow speed operation. It does for fast speed operation.

So while an FCM issue might be keeping your fans from working in fast speed, it will not impact your slow speed operation from the thermoswitch.

It could be a wiring issue. These cars often have wiring issues from vibration causing fretting. Even the plastic wire loom can rub through the insulation and the wiring.

Check your wiring path resistances, and check for voltage drop when you are trying to run the fans. The voltage on pin 2 should not drop more than about 0.5 volts when you try to start the fans.

Are you sure you are getting a good electrical contact on your jumper?
 

jun_1.8T

Member
Joined
May 31, 2009
Location
GTA, Ontario
TDI
Jetta
thanks again dan

so what would be my next step now??? yes...im getting good connections from my jumper. i took voltage readings from pin #2 of the thermo switch harness before i tried jumping it to pin#1...and took it again when jumped the two together and i wasn't losing any voltage at all. but still my fans wont work if i jump it through the thermo switch harness. so i tried putting power again directly to my fans and they both worked fine.

so should i start splicing through the wiring and trace the path of the thermo switch harness??? from the facts i've told you so far....are you able to confirm that this is not an FCM issue???
 

DanG144

Top Post Dawg
Joined
Aug 2, 2007
Location
Chapin, South Carolina, USA
TDI
2005 A4 Jetta 5spd
The next step would be to check the wiring, and find out why your slow speed fans will not work from the thermoswitch.

A bad FCM will not prevent this.

After you get this fixed, you can check the operation again with the AC start signal. That will test slow speed operation through the FCM. If this works, and the clutch is engaging, then the most important functions of your FCM are working, and I would not worry about it.

Unless you test that the FCM properly handles every possible combination of input signals, you will not know if you have a bad FCM. But this seems overkill - this is not a nuclear plant.

You might find that the same wiring issue is preventing operation from both the FCM and the thermoswitch.

Many of these wiring issues are found just by inspection. Once you start opening the split loom conduit they can often be easily seen.
 

jun_1.8T

Member
Joined
May 31, 2009
Location
GTA, Ontario
TDI
Jetta
hi dan,

i don't know what happened when i first tried to power up my fans this morning because they worked fine. but then when i got home last night i tried powering them up again but this time they did not work. the passenger side is completely dead and the drivers side only works on high speed.

i did all the checks from the FCM output and they are all good. both high and low speed are getting 12.5 volts from the FCM and also from the thermo switch. so i guess those two are good and it is really my fans that has died on me.

now...how hard it is to pull out the fans??? it looks like a big job. i was trying to study on how to take them out of the rad and all i can see are 4 torx screws. is that what holds it??? but the problem is that one of them is being blocked by a small silver canister(i dont what that is). is there a DIY i can follow on how to remove the fans from the rad??

thanks a lot!
 

DanG144

Top Post Dawg
Joined
Aug 2, 2007
Location
Chapin, South Carolina, USA
TDI
2005 A4 Jetta 5spd
Each fan has three 27 torx fasteners that hold it in place, remove the pigtail connections, pull the fans out the top. It takes a bit of maneuvering, sometimes hose supports have to be moved (in New Beetles mainly.) The Jettas/Golf come out pretty easily.

You probably have a heater, seeing where you live, that will make it a bit harder.

You have to get some of the torx fasteners from the bottom, so you have to remove the skidplate/belly pan.

The connectors for the pigtails MUST be pryed or rolled out of their plastic holder before squeezing and disconnecting the connectors.

The fan repair DIY takes it from there.
 

lovemybug

Veteran Member
Joined
Mar 11, 2007
Location
SE Wisconsin
TDI
2002 Red Beetle
Checked mine last night. Both fans were working. So far so good. Now to change out my cabin air filter one of these days.
 

VagPhillips

Well-known member
Joined
Sep 13, 2007
Location
Suwanee, Georgia
TDI
2005.5 pkg 2
Good advice, wish I had read it sooner

I thought it was a bad compressor or fan clutch.
AC not cold when idling or around town. Then it started making an awful noise, cutting on and off.
Looks like I let mine go too far and am looking at a difficult or expensive repair.
This board has saved me more times than I can count, should have checked here when I first noticed a problem.
Lesson learned.
 

andreigbs

Veteran Member
Joined
Sep 27, 2004
Location
Walworth Co., Wisconsin
TDI
N/A
Thanks Dan, great troubleshooting guide you've put together.

Checked the fans on my '04 TDI this morning, both fans run on low.

I may still try that compressed air-in-a-can cleaning for the fan motors, just to flush out any dirt or debris. Keep up the great work.
 

Ferg

Active member
Joined
Aug 16, 2005
Location
Ogden, UT
TDI
2010 Jetta Cup Edition
My fans work. I have replaced both in the last 6 months.

My A/C tends to work fine for awhile and then will start to kick on and off very rapidly so to be noticble when driving (small jerking feeling)

When driving in congested traffic or starting and stopping, sometimes the A/C stops working altogether.

I read that someone had an issues with the "30A fusible link". Could this be what I am experiencing? Where is it and how do I test it. Any other ideas?

Thank you

Ferg

2003 TDI Jetta Manual Transmission
 

DanG144

Top Post Dawg
Joined
Aug 2, 2007
Location
Chapin, South Carolina, USA
TDI
2005 A4 Jetta 5spd
Ferg,
This sounds as if it is cycling on and off on refrigerant pressure. Does the behavior start within a few minutes of engine starting from cold? Or does the behavior only happen when the engine has had time to warm up?

You say you replaced your fans. Are you sure they both still come on when the AC is turned on?

Low refrigerant pressure will prevent both the fans and the AC clutch from energizing.

High refrigerant pressure will kick the fans to high speed.

High High refrigerant pressure will disengage the AC clutch.

The pressures have to be checked with a gauge set, and the output of the pressure sensor needs to be checked for at least one given pressure. There is a table in the pdf linked in the first post about A4 Air conditioner troubleshooting that gives the pressure/signal relation and the approximate actuation setpoints.

If the ECU is sensing that the car is getting too hot then it will shut off your AC compressor.

  1. Remember that the displayed temperature is not what the ECU sees.
  2. The displayed temperature will be dead center from 167 to 225 degrees F, no matter what the actual temperature is.
  3. The ECU gets its signal from an electrically separate temperature sensor than the gauge (even though they are both mounted in the same metal/plastic body.)
 

visionlogic

Veteran Member
Joined
Aug 23, 2006
Location
Daphne, AL, USA
TDI
2002 Jetta TDI
Anyone have any tips for balancing a new fan, or is it, as I suspect, just a matter of trial and error? My large driver side fan was dead -brush holders melted and ruined. Installed a new fan. But now there is a noticeable "vvvvvvv..." vibration sent through the unibody that was absent with just the small passenger side fan running. I see that one fan blade has a small metal spring clip on it that I assume was added for balance, but it's not doing a very good job.

EDIT - 6/15/09: Fixed! I grabbed a bridge clip used on telephone punch-down boards and slid it onto a fan blade next to the one that currently has the factory clip installed. Good luck! The clip fits nice and snug and the bad vibe has completely dissipated!
 
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Ferg

Active member
Joined
Aug 16, 2005
Location
Ogden, UT
TDI
2010 Jetta Cup Edition
Dan:

I had my refridgerant replaced last fall. The A/C wasn't working at all and I tied it to the fans. I ended up replacing both. The fans are working. I don't know about the pressure. I had my local shop do the work. I will have to get the pressure checked.

It happens when the car is warmed up.

I have had about three to five instances where the actual car temperature gauge wouldn't work. I was going to replace the sensor, but it has been working fine for the last few months. It happened mostly when it was raining. If both sensors are housed in the same plastic module, could this be the problem?

Thanks,

Ferg
 

jun_1.8T

Member
Joined
May 31, 2009
Location
GTA, Ontario
TDI
Jetta
ok....im having a hard time figuring out how to take my fans off. my fans are both inside this fan shroud that is bolted on the the radiator on four sides with a torx screw. do i need to take out the shroud first before i can access my fans??? if so...one of the four torx screws is being blocked by a small "metal canister" like assembly. whats the easiest way to take out my fans???

also...i could not test my bigger fan if it works on both low and high speeds. i have confirmed that my smaller fan is dead. but i've seen my bigger fan work when i turn on my ac...so does that mean it is still good?? i just want to make sure as i need to order my fans online and dont want to order something i dont really need.

thanks!
 

DanG144

Top Post Dawg
Joined
Aug 2, 2007
Location
Chapin, South Carolina, USA
TDI
2005 A4 Jetta 5spd
On the Jetta you should be able to take off only the offending fan.

Unhook the electrical connector by rolling it out of its mounting bracket - You have to get it out of the bracket to unplug it. Then it opens like a typical VW electrical connector - squeeze the end of the lever (nearest the wires) in the rectangular area sticking out of the connector body. Then pull it apart. They tend to stick.

There are three 17 torx holding it on end the end of the spider legs. Leave the shroud in place. Then remove the fan out the top and either repair or replace the old one.

If a fan is running in slow speed when you turn on the AC, then I would leave it alone.
 

DanG144

Top Post Dawg
Joined
Aug 2, 2007
Location
Chapin, South Carolina, USA
TDI
2005 A4 Jetta 5spd
Jun,
You will also have to get up on ramps or jackstands and get the belly pan off in order to get to one or two of the 27 torx holding the spider legs in.

The spider leg mount come out with the fan.
 

dougsbug

Veteran Member
Joined
Sep 15, 2008
Location
Fremont, Michigan
TDI
'02 Beetle
Hello,
I am a noob, (sort of.) I just bought an 06 Jetta TDI. The AC does not work, fans do not come on with or without the car running, on any fan speed. I have read the posts and trouble shooting PDFs but am unclear on what applies to this particular year/car. As I said it is an '06 with "Climatic". Is this "manual" or is it Climatronic?
The AC blows warm, (at least not cold.) The compressor does not come on as far as I can see/feel. I visually inspected the fuses but will put a fuse tester on each one. I have a mulimeter but not totally sure how to set it/operate it, (but I can follow directions ;)) Could someone give me some direction? Suggest a good AC guru or shop in my area? (Fremont, MI, Close to Grand Rapids or Muskegon, home of Gerber Baby Food.)

If I understand what I have read so far, the compressor will not come on if the fans won't operate. The fans won't come on due to corrosion or low R134. So the first thing is to verify if the fans work on their own. Right?

Are there any photos to identify my fuse block? Thanks.
 
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DanG144

Top Post Dawg
Joined
Aug 2, 2007
Location
Chapin, South Carolina, USA
TDI
2005 A4 Jetta 5spd
The information in this thread is applicable mainly to A4's. Sorry.

Climatic is a different A/C system than the older manual A/C system.

I recently did some looking at the Climatic system for another thread.
http://forums.tdiclub.com/showthread.php?t=249313&highlight=climatic look mainly at post #16.

I do not have a manual for this car and system, and so can help very little more.

In the older systems as long as there was power to the fans, and a minimum refrigerant pressure condition was met, the AC clutch would engage and run for up to a minute, then it would reach an overpressure condition and shut the clutch off.

In the older systems if the refrigerant pressure was low, then it would prevent the fans from working and the A/C clutch from engaging.

Your car has a different set up, but I would check all the fuses, then check the refrigerant pressures. If they are low, take it to a shop for repair. If the refrigerant pressures are good, I would buy a Bentley manual and start troubleshooting myself.
 
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