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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.

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Old February 23rd, 2020, 18:12   #1921
RayBrubaker
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Working on a 99.5 A4 Jetta ALH, Replaced a blown-up AC high/low pressure switch and charged the system. Compressor clutch engages but the fans don't come on. All fuses are good. Checked fans per the beginning of this thread and they work on low and high when jumping at the radiator temp sensor plug. Before I buy a FCU I want to confirm my diagnosis. The FCU is working partially since it turns on the compressor and the high speed fan (when jumpered). Is it likely that one mode of the FCU would fail? I've tried different searches on this thread but haven't found exactly this situation. Thanks for your help.
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Old February 24th, 2020, 11:19   #1922
Andyinchville1
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HI,

Checked my fans today and they work .... whew ... I could not remember hearing then run.

Good thread to make sure stuff is ready when it starts getting hot.

Thanks!
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Old May 16th, 2020, 10:00   #1923
gusechopper
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The t14/6 pin has less then .5 when the engine is off and 58+ when the engine is off. i can not find a break in the line. any one have an idea on what i should look at next?
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Old June 3rd, 2020, 15:17   #1924
jelmerfud
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Default AC Problem Mk4 Jetta

I am a brand-newbie to the TDIclub forum, and have appreciated the tips and the help in this thread about A/C issues.
I have a 2003 Mk4 Jetta and the A/C is not working this spring (It has worked flawlessly up until this season).
It is a manual control climate system, and the AC button illuminates and the cabin fan works - it is blowing warm air, however. It sounds like the engine RPM dips when the AC button is engaged, but I could not hear the compressor engage.
Thinking it just needed a shot of refrigerant, I tried that first. I quickly found that the pressure in the AC system was very high - due to the fact that the compressor was NOT running.
I tried the radiator and condenser fan test from the beginning of this thread. I found that ONLY the large fan on the driver's side worked in slow speed with the key ON and the AC button ON. The Passenger side fan did not run. It does seem to spin freely by hand.
I checked the fuses over the battery, and everything looks good - fuses are good, and no sign of melting or corroded terminals or contacts.
I am at a loss for what to try next. I am looking to tap the community expertise here - Would the FCM be the most likely culprit? Would it be the fan itself? I can't see where replacing the fan would make the AC suddenly engage and start to work (?).
I have not tested the wire leads at the passenger fan to see if it is getting power. That is my next planned step. If it IS getting power, then I have to assume that the passenger side fan motor burned up - but why would that keep the AC from running if the large drivers side fan works?
Grateful for any thoughts or advice you can bestow upon this frustrated newbie. Thanks !!
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Old June 4th, 2020, 11:36   #1925
SilverGhost
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If only one fan turns, then you need to replace both fans. I say both fans because when one fails, the other is usually ready to fail, gets knocked around when changing the bad fan, and has been working harder to compensate for the failed fan. Also the fans are wired together, so both should always run together.

Pressure does not mean the system is charged enough. My guess is that the system pressure got too high with only one fan running and may have vented some Freon. Possibly not enough Freon left for the system to start up.

I would get new fans (like IDParts sells) installed, then find a shop to recover and recharge the system. That way you can find out how much Freon is really in the system. If it still doesn't work, come back and ask questions. There are some good HVAC people who can help.

Jason
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Old June 4th, 2020, 20:40   #1926
ymz
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Quote:
Originally Posted by SilverGhost View Post
If only one fan turns, then you need to replace both fans. I say both fans because when one fails, the other is usually ready to fail
One of our cars had the 2nd fan fail 3 months after the first... the other cars only had the one go bad... the other fan kept going for years... (over 200,000 miles... and still going...) YMMV...



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Old June 5th, 2020, 07:59   #1927
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Quote:
Originally Posted by ymz View Post
One of our cars had the 2nd fan fail 3 months after the first... the other cars only had the one go bad... the other fan kept going for years... (over 200,000 miles... and still going...) YMMV...



Y.
And I can't count how many times I sold a customer the one fan that failed, only to have the other fan not work after the repair. Labor cost money to pay someone and its the same for one fan or two.

Now if you do it your self it becomes a question of how much do you value your time? I have two little kids and have no extra time to be taking the fans out more than once. So I get OEM and do both so it's one and done. If' you're single or just have plenty of free time, then take them out, take the motor apart, and fix the brushes.

Jason

BTW - older A3 Jettas only have one motor and a belt drives the other fan. Not sure if B4 Passat is the same.
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Old June 5th, 2020, 08:23   #1928
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I hate these disagreements where both sides are right!
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Old June 10th, 2020, 09:50   #1929
Boondoggle
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I have a 2002 Beetle TDI and the AC is not working, and when I turn on the key, and press the AC button, neither radiator fan is running. It is 80F. I checked the fuses above the battery, and the fuses appear good. what is the next thing I need to check to diagnose this problem.
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Old June 10th, 2020, 11:29   #1930
BobnOH
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Quote:
Originally Posted by Boondoggle View Post
I have a 2002 Beetle TDI and the AC is not working, and when I turn on the key, and press the AC button, neither radiator fan is running. It is 80F. I checked the fuses above the battery, and the fuses appear good. what is the next thing I need to check to diagnose this problem.
Start reading back at Post #1. All your answers are here. Dan did a very thorough job with this, contains much more than just the fan bidness.
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Old July 7th, 2020, 14:15   #1931
colemanp2
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Default Fan problem

Question if 1 fan is bad will it keep both fans from starting in low speed pr should i look deeper like the fan control relay also
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Old July 8th, 2020, 17:39   #1932
wonneber
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Follow the "Check your radiator/condenser fan operation NOW" thread in the top of the forum list.

If it's electrically dead I would think the other should work.
They both get power together.
They both ground to the same point.
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Old Yesterday, 08:53   #1933
BobnOH
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Quote:
Originally Posted by colemanp2 View Post
Question if 1 fan is bad will it keep both fans from starting in low speed pr should i look deeper like the fan control relay also
Start reading back at Post #1. All your answers are here. Dan did a very thorough job with this, contains much more than just the fan bidness.
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Old Yesterday, 11:47   #1934
Rabbijalabbi
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Default AC problems

Ok, so I started at the beginning of this thread, but I have not read through the entire thing...
I have '02 Jetta TDI and AC compressor clutch is not engaging. Started trouble-shooting fan electrical system, and found that when key is turned on, and AC button is pressed with fan turned on, radiator fans do not operate at low speed. However, when I remove fuse 16 on the inside cabin fuses, they do turn on. Does this tell me where the problem is? Fuse 16 is a 10 amp fuse that is good. I traded it out with other working fuses to make sure.

Last edited by Rabbijalabbi; Yesterday at 12:29.
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Old Yesterday, 13:49   #1935
Rabbijalabbi
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ok, so I connected 12v directly to ac compressor and it does not engage clutch...I believe this tells me I have a bad compressor, correct?
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