BettyWhite
Member
Yes, when the car is cooled down, air is off, AC off and/or on, key on, the passenger side fan turns on.
Is there anyway to find the root cause of the driver side fan failure?
Check your radiator/condenser fan operation NOW
- Thread starter DanG144
- Start date
Is there anyway to find the root cause of the driver side fan failure?
AnotherPerson
Veteran Member
It's just a bad fan I'm sure. They go out way more than you would expect. As for key on fan on. Your temp sensor is saying the car is warmed up or overheating and needs cooling. If you look back on this post they have diagnostic info on how to verify this.
DanG144
Top Post Dawg
I disagree. BettyWhite's problem is probably fuse 16 blown, which causes both fans to run. Except one fan has failed.
These cars engine temperature controls only extremely rarely need to run the fans; it is very unusual for the engine to need cooling after shutdown. This is not a Honda gasser, where that is normal.
Check fuse 16 in the cabin fuse panel. Going from memory here, but pretty sure that is it.
These cars engine temperature controls only extremely rarely need to run the fans; it is very unusual for the engine to need cooling after shutdown. This is not a Honda gasser, where that is normal.
Check fuse 16 in the cabin fuse panel. Going from memory here, but pretty sure that is it.
DanG144
Top Post Dawg
The root cause of the driver's side fan failure is simply due to design. It is a DC brushed fan, and they have a limited life - brushes wear out.
Think how many hours you have run your AC. That is how many hours that fan has run in the last 14 years.
Think how many hours you have run your AC. That is how many hours that fan has run in the last 14 years.
AnotherPerson
Veteran Member
What does fuse 16 run just so I'll know. I've only ever seen fans run after the fact when the sensor is showing a lot higher than it is. Or maybe also traffic in desert heat. That might too
Quanger
Veteran Member
I recently had my AC crap out as I was driving last week. Checked it out and it turns out both my fans crapped out (They didn't run with the AC turn on, ignition on). I was Getting high resistance on the fans when measuring so the fans were replaced. But now my AC isn't working, I assume the compressor is kaput. I notice the compressor barely spins.
Im not sure if it's just the clutch or do I have to replace the whole compressor? I'm hoping not to have to break the circuit.
Do dead fans automatically kill the compressor or is there some kind of safety?
Im not sure if it's just the clutch or do I have to replace the whole compressor? I'm hoping not to have to break the circuit.
Do dead fans automatically kill the compressor or is there some kind of safety?
BettyWhite
Member
I checked out Fuse 16 in the Cabin, a 10 Amp Fuse, and it's not blown. I swapped it with another non-blown 10 Amp Fuse to see if it was just the terminal connections that could impact performance, but se la vie, the passenger side fan still kicks on when I key on.
I'll pull out my Bentley manual in the morning and double check Fuse 16 was the one we were looking for. Thanks for the tip.
Thanks for the root cause explanation.
DanG144
Top Post Dawg
Betty,
Good move to go for the Bentley. Look on page 38/3.
Fuse 16 provides control power and operating power to the FCM. On an otherwise healthy Mk IV, if you pull this fuse, you get the fans to run as you describe.
I would next look at your FCM 14 pin connector, and verify that the pin 4 is getting power - this is what fuse 16 feeds.
It is not unusual in the snow belt for this wire connection to suffer galvanic corrosion and break off. Then you get exactly the same symptoms as if the fuse is blown. More than one of your compatriots have had this happen, especially if they don't have a lower engine cover (belly pan).
I know my fan comment was trite, but those OEM fans typically run thousands of hours and years before they fail. I don't think any brushed motor will last longer...though they may last longer if you move the slow speed resistor out of the motor housing. You can find some English guys selling a PWM controller that bypasses the slow speed resistor and pulses the fast speed to control speed. They did this because in early configurations the slow speed resistor was too close to the brushes, and would melt the brush holders (if plastic) or even melt the solder joints. Later configurations moved the resistor further away (and used crimped connections) but still left it inside the housing. As is fairly common on these cars, you can follow threads on this issue for hours.
If you look in post #1, you can see one method to repair the fans. If you can source metal brush holders with new brushes, you could probably make the fans last a long time.
Good move to go for the Bentley. Look on page 38/3.
Fuse 16 provides control power and operating power to the FCM. On an otherwise healthy Mk IV, if you pull this fuse, you get the fans to run as you describe.
I would next look at your FCM 14 pin connector, and verify that the pin 4 is getting power - this is what fuse 16 feeds.
It is not unusual in the snow belt for this wire connection to suffer galvanic corrosion and break off. Then you get exactly the same symptoms as if the fuse is blown. More than one of your compatriots have had this happen, especially if they don't have a lower engine cover (belly pan).
I know my fan comment was trite, but those OEM fans typically run thousands of hours and years before they fail. I don't think any brushed motor will last longer...though they may last longer if you move the slow speed resistor out of the motor housing. You can find some English guys selling a PWM controller that bypasses the slow speed resistor and pulses the fast speed to control speed. They did this because in early configurations the slow speed resistor was too close to the brushes, and would melt the brush holders (if plastic) or even melt the solder joints. Later configurations moved the resistor further away (and used crimped connections) but still left it inside the housing. As is fairly common on these cars, you can follow threads on this issue for hours.
If you look in post #1, you can see one method to repair the fans. If you can source metal brush holders with new brushes, you could probably make the fans last a long time.
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BettyWhite
Member
Dan, I wasn't able to locate page 38/3 in the Bentley, rather my book stops at 37-60 Automatic Transmissions and then continues onto 39-1 Differential and Final Drive, any section numbered 38 is missing. I found section 19-7 and 97-3 to help troubleshoot the thermo-switch/FCM and the fuse panel, respectively. I checked out fuses S164 and S180 and verified they're good, so that's good news. Cleaning the terminals would have a been a good idea for S180, though, I'm sure where you get a terminal cleaning tool for fuses, any idea? Let me know if there are other helpful sections.
Until I popped the hood of the car, I was confused by the orientation of Image 0024245 in section 19-7 of FCM.... Now I see that it's under the battery trey (Google images helped affirm this too). Being that I just lost daylight, I will get under the car tomorrow and drop my skid plate and be able to get access to the FCM.
Thanks for the info about galvanic corrosion, I recently added a DieselGeek Panzer Skid Plate this past October 2015 for engine protection. The previous owner said the OEM cover had fallen off two winters ago and as such drove the car without it.
Is the FCM 14 pin connector on the left or right? I'm assuming the left based on watching this mechanic check for continuity across the relay. Though, I'm assuming the FCM will be the same pin configuration for my TDI as a VR6, let me know if this assumption is wrong.
Lastly, appreciate ya expounding on the root cause failure and way to fix the fans.
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CrustyOreo
Veteran Member
Yep it is the clutch, I turn the a/c off and it's silent!
I have no desire to change the clutch, another summer with out a/c!
ymz
Top Post Dawg
- Joined
- May 12, 2003
- Location
- Between Toronto & Montreal
- TDI
- 2003 Jetta TDI Wagon, 2003 Jetta TDI Wagon
Could you elaborate on what part of the clutch would be making the noise? We have the noise, but the A/C works (for now)... I have a "spare car" from which I can borrow parts...
Yuri
DanG144
Top Post Dawg
38/3 is a schematic page number, not a regular page number, sorry for the confusion
The 14 pin connector is the one on car left. the 4 pin one is on car right.
The 14 pin connector is the one on car left. the 4 pin one is on car right.
DanG144
Top Post Dawg
Yuri,
it is usually the outer edge, where it clamps onto the drive pulley.
Where you live, it may easily be rust.
I would take the belt off and spin the carrier bearing by hand, just to make sure it is not the carrier bearing, but if the noise stops with the clutch 95% of the time it is the clutch rubbing faces.
Turn the center shaft of the compressor with your fingers, ensure it is smoothly turning with only finger pressure, no catches or glitches. This will ensure it is not increased resistance to turning by the compressor that is causing the clutch to slip and squeak.
it is usually the outer edge, where it clamps onto the drive pulley.
Where you live, it may easily be rust.
I would take the belt off and spin the carrier bearing by hand, just to make sure it is not the carrier bearing, but if the noise stops with the clutch 95% of the time it is the clutch rubbing faces.
Turn the center shaft of the compressor with your fingers, ensure it is smoothly turning with only finger pressure, no catches or glitches. This will ensure it is not increased resistance to turning by the compressor that is causing the clutch to slip and squeak.
ymz
Top Post Dawg
- Joined
- May 12, 2003
- Location
- Between Toronto & Montreal
- TDI
- 2003 Jetta TDI Wagon, 2003 Jetta TDI Wagon
Carrier bearing is fine, and the compressor spins easily (possibly too easily?) The noise is quite pronounced...
If I have time to play (ha, ha!), I may try to replace the clutch plate - since I have the spare sitting on a shelf - I needed to "borrow" the coil from the parts car already... for our other car...
Yuri
If I have time to play (ha, ha!), I may try to replace the clutch plate - since I have the spare sitting on a shelf - I needed to "borrow" the coil from the parts car already... for our other car...
Yuri
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DanG144
Top Post Dawg
The compressor should spin very easily. It is basically doing no work, maybe 5 cc of pumping per revolution, and the pressure is the same on both sides, so all you should feel is the friction of the innards.
DanG144
Top Post Dawg
You may want to check the shimming of your compressor clutch. It may work fine if it is shimmed right. I would have to search for the gap specs.
I must say that gap setting has never shown as an operating issue to me, but it has to other folks.
I must say that gap setting has never shown as an operating issue to me, but it has to other folks.
ymz
Top Post Dawg
- Joined
- May 12, 2003
- Location
- Between Toronto & Montreal
- TDI
- 2003 Jetta TDI Wagon, 2003 Jetta TDI Wagon
This just came on recently... (meaning, this season... could be rust from Winter... the cure being ??????)
Yuri
Yuri
DanG144
Top Post Dawg
If it is just rust, you may be able to silence it and make it grip by just taking off the outer clutch face and using some 180 grit sand paper on the rubbing surfaces (face and pulley). Don't try to make them pretty, just get the gross stuff off. A wire brush would probably also work.
I fixed the fans...it seemed that when i removed them for a DIY fix...after putting them back in i didn' t plug them right and got unpluged.
Now the problem is that the air that comes out is not Alaska cold( as someone here mentioned).
Plus...the air coming from the vents when the fan is at 4( MAX) is not as "strong" as i remember it.
1. Could i have caused a problem by running the A/C with the rad. fans not working???
2. Could it be a blockage in the blower tubes or mixing hot air with cold air??
Now the problem is that the air that comes out is not Alaska cold( as someone here mentioned).
Plus...the air coming from the vents when the fan is at 4( MAX) is not as "strong" as i remember it.
1. Could i have caused a problem by running the A/C with the rad. fans not working???
2. Could it be a blockage in the blower tubes or mixing hot air with cold air??
AnotherPerson
Veteran Member
Mine is properly charged, etc etc. at idle during the heat it isn't ice cold. Test that with the rpm around 1500. As far as blowing less lookup the mix door repair. Mine has the same issue and it causes it to blow air on the floor and defrost too.
I'm personally one day going to replace the whole evap system under there as its a ton of work. A new replacement system with all the mix doors and casings etc is $300. Labor. 6-8hours :/
AnotherPerson
Veteran Member
Heres the link. Its ALOT of work. I just deal with it coming out all the spots for now.
http://forums.tdiclub.com/showthread.php?t=413341
http://forums.tdiclub.com/showthread.php?t=413341
BettyWhite
Member
Dan, with key off, I grounded my test light to the chassis and put the test probe on T4's Pin 4 (left) in the FCM, the test light didn't light up.
Also, maybe you could help me clear up some confusion. We have been referring to the 14 pin connector, but the connector I'm seeing has 4 pins (left). Why is the left connector a 14 pin connector when it doesn't have the physical hardware to represent it as such?
My main motivation for asking the above question came after looking at Wulee's Pin Out guide of the J293, I noticed T14/4 was exact component I wanted to test but according to the Bentley FCM Picture, T4/4 is the pin representing T14/4. Are the T4 and T14 nomenclature's interchangeable?
Lastly, just as a heads up, if I ask some amateur-ish questions about electrical work I've been re-learning/learning some electrical basics. Feel free to point me in the direction of useful electrical tutorials and videos.
Thanks
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DanG144
Top Post Dawg
good question.
The pin count identifies the connector. So the T14 DOES have 14 pins. The T4 Does have 4 pins. Not sure where we got twisted. I am growing dyslexic as I age.
Maybe this? Everything in the car is defined by CAR left or CAR right - as if you were sitting in the car looking forward.
The pin count identifies the connector. So the T14 DOES have 14 pins. The T4 Does have 4 pins. Not sure where we got twisted. I am growing dyslexic as I age.
Maybe this? Everything in the car is defined by CAR left or CAR right - as if you were sitting in the car looking forward.
DanG144
Top Post Dawg
Do you have a Bentley manual or other source of a schematic?
BettyWhite
Member
That's good to know the pin count identifies the pin connector. We can work with CAR left and CAR right.
Do you have a picture of the T14 connector? I feel confident I found the T4 and T8 connectors on the FCM. A mental image of the T14 connector would be superb.
Yeah, I have my Bentley opened up to Repair Manual page manual 97-350 for schematic No. 38/3.
DanG144
Top Post Dawg
Page 10 of the A4 Troubleshooting guide, rev 7 in the first post of this thread has a picture of both the T4 and T14 pin connectors on the FCM
There is no T8 connector on the FCM. There is on the switch and control module in the dash, if you are talking about T8b.
Ah, I looked at your photo. That is from a very early VW, not sure how early, as even the Mk IIIs had a 10 pin connector, and will only serve to confuse MK IV owners.
Look also at page 11 of the troubleshooting guide.
There is no T8 connector on the FCM. There is on the switch and control module in the dash, if you are talking about T8b.
Ah, I looked at your photo. That is from a very early VW, not sure how early, as even the Mk IIIs had a 10 pin connector, and will only serve to confuse MK IV owners.
Look also at page 11 of the troubleshooting guide.
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BettyWhite
Member
Good stuff, I'm all sorted on what the FCM looks like now, thanks Dan.
Today I focused on running through the A4_Air_Conditioning_Troubleshooting_Rev_7 PDF to determine if the driver side fan needed to be replaced, turns out it did. I replaced the driver side fan unit and now have both low and high speed operation on the passenger and driver side fans. See Dropbox Link 1 for the finished unit:
Link 1: https://www.dropbox.com/s/st3boo2pi2qrnyp/IMG_1621.JPG?dl=0
However, I still have the previous outlying issue at key on. At key on with AC on or off, the cooling fans both immediately turn on to low speed. At key off, the cooling fans run in low speed for 5 minutes then power down. I recorded a video of the behavior when I was using a fused jumper on pins 2 and 3 of the thermoswitch:
Link 2: https://www.dropbox.com/s/pffuz74gl829t2h/IMG_1627.MOV?dl=0
Dan, today I measured the pin out voltages and double checked the fuses, here's a summary of where I'm at.
S180 = Good
S164 = Good
Cabin Fuse 5 = Good
Cabin Fuse 16 = Good
Cabin Fuse 25 = Good
Thermoswitch Pin 2 = 12.20 V
T4 Connector – Key On and Key Off
T4/1 = Input, 12.37 V
T4/2 = Output, N/A no power here
T4/3 = Input, 12.36 V
T4/4 = Output, N/A no power here
T14 Connector – Key Off - All pins not listed had a reading of 0 Volts
T14/2 = 0
T14/4 = 0.33 up to 1.47
T14/9 = 0
T14/11 = 0
T14/13 = 0.10 to 0.11 (fluctuating voltage)
T14 Connector – Key On - All pins not listed had a reading of 0 Volts
T14/2 = 2.82
T14/4 = 0.30 up to 0.49
T14/9 = 12.33
T14/11 = 3.57
T14/13 = 5.6 to 11.8V (fluctuating voltage)
Let me know if any of the links don't work and thanks for your help
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DanG144
Top Post Dawg
Your immediate problem is a lack of power on T14/4.
Check the wire by piercing it, to see if it has voltage.
The most common fail point, after the fuse, is the electrical joint right at or inside the T14.
If that is the problem, you can buy a repair wire at VW and replace that section of wire and the connector.
Check the wire by piercing it, to see if it has voltage.
The most common fail point, after the fuse, is the electrical joint right at or inside the T14.
If that is the problem, you can buy a repair wire at VW and replace that section of wire and the connector.
SilverGhost
Veteran Member
- Joined
- Mar 25, 2005
- Location
- Back in So Flo - St Lucie
- TDI
- '05 Golf - totaled :(, wife's '13 Beetle - buy back, TDIless
If you must do this, PLEASE FIX THE WIRE WHEN YOU ARE DONE. Can't count how many have pierced wires that later corrode. Or have bent contacts, or don't make contact. I know it is the most practical way to test, but please don't make new problems for yourself, down the road.
Jason