No cooling fans with AC on

Stamie

Active member
Joined
May 20, 2010
Location
Long Island, NY
TDI
02 Golf GLS 324,000 all stock original..... 2013 Passat tdi se 62,000 same
Any one.... have a little problem... '13 Passat tdi A-6....no fans at all until coolant reaches temp. thus, no AC until fans come on. My '02 Golf tdi had the same problem which was fixed with a cooling fan control module. Cant find manual for the Passat....can't troubleshoot without one. Maybe a relay? Or a module? Anyone?

Otherwise, AC is blasting cold....once the fans come on.
 

compu_85

Gadget Guy
Joined
Sep 29, 2003
Location
La Conner, WA
TDI
... None :S
Use VCDS to see if the climate control head is commanding the fans to come on. I did notice on our '12 that it waits a moment after starting the compressor to start the fans.

-J
 

Stamie

Active member
Joined
May 20, 2010
Location
Long Island, NY
TDI
02 Golf GLS 324,000 all stock original..... 2013 Passat tdi se 62,000 same
i dont have access to one but I'm not experiencing a delay.....fans dont come on at all until i reach temp.
 

compu_85

Gadget Guy
Joined
Sep 29, 2003
Location
La Conner, WA
TDI
... None :S
Well does the AC cool when you're moving? It turns them on based on pressure. If the AC is broken or low it might not turn the fans on.

You can check the AC pressure with VCDS too.

This is from our Touareg, the Passat is similar:



-J
 

Stamie

Active member
Joined
May 20, 2010
Location
Long Island, NY
TDI
02 Golf GLS 324,000 all stock original..... 2013 Passat tdi se 62,000 same
Thanks, AC works great once the fans come on, whether car is moving or stationary. Problem is that the fans wont turn on until coolant temp. reaches about 180 deg. even with the AC selected on.

Cold start...no AC. Have to wait for engine to heat up before the fans come on, then the AC is very cold.
 

DaveTC

Well-known member
Joined
Sep 14, 2013
Location
Minneapolis, MN
TDI
2013 Passat TDI SE
The VW manual that I have is titled Refrigerant R134a Servicing. The coolant fan control module does control the A/C clutch and the coolant fan according to the manual, so it could be the problem.

I think that you need more information for a diagnosis. I would tent to lean towards believing that it is an undercharged system like compu_85 is suggesting.

The A/C on my truck was not working this week. The compressor clutch was not cycling on. I put a gauge set on it and the the pressure was about 20 PSI without the compressor running. As soon as I added some Freon, the clutch started working. I did not have the fan shroud on and the cooling was poor, because air was not being pulled across the condenser. A fan that is not operating could do the same thing.

My guess is that when the car warms up it increases the pressure enough to trip the pressure switch. It looks like the VW system will not turn on if the pressure is below 29 PSI. If your pressure is right on the edge, engine heat could heat up the Freon enough to trip the switch. With that theory though, the A/C should not be working great since the system is probably undercharged. It could also be that the coolant fan control module is not turning on the fan and it is just working inefficiently. Assuming that the clutch is visible like in my truck, you should try to determine if the clutch is cycling. If it is operating, it would shoot down the low Freon theory.
 
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whitedog

Veteran Member
Joined
Jul 12, 2004
Location
Bend, Oregon
TDI
2004 Jetta that I fill by myself
Dave, this Passat doesn't have a cycling clutch. The pump is always turning when the engine is running and the system is controlled by an electronic control valve.

Search for "delayed Air conditioning", "RCV" or "refrigerant control valve."
 

DaveTC

Well-known member
Joined
Sep 14, 2013
Location
Minneapolis, MN
TDI
2013 Passat TDI SE
Dave, this Passat doesn't have a cycling clutch. The pump is always turning when the engine is running and the system is controlled by an electronic control valve.

Search for "delayed Air conditioning", "RCV" or "refrigerant control valve."
After I wrote that, I went out to my car and did not hear the clutch cycling. That would explain it.
 

Stamie

Active member
Joined
May 20, 2010
Location
Long Island, NY
TDI
02 Golf GLS 324,000 all stock original..... 2013 Passat tdi se 62,000 same
Correct and thank you, Refrigerant charge is sufficient and compressor runs with AC selected on. Again, fans don't run until coolant reaches operating temperature around 180 deg.F. At which time the fans come on and AC is ice cold. Similar problem with my '02 Golf was result of a bad Fan Control Module...very cheap and easy fix. Can't seem to find the Bently for cars after 2010 or so....which manual did you reference Dave? This is for a '13 Passat tdi.
 

VeeDubTDI

Wanderluster, Traveler, TDIClub Enthusiast
Joined
Jul 2, 2000
Location
Springfield, VA
TDI
‘18 Tesla Model 3D+, ‘14 Cadillac ELR, ‘13 Fiat 500e
You could be experiencing a failing RCV, as mentioned by whitedog. I was speaking with another Passat owner this past weekend who was experiencing an RCV failure. I was hoping the Passats wouldn't be plagued by this problem, but it appears that they might be.

Symptoms usually include a 1 to 5 minute delay in air conditioning. During that time, you may have very little cool air, or none at all.

The part is about $80 and can be installed by a competent A/C shop. If you go to Volkswagen, they will charge you for an entire new compressor because they are not allowed to change just the refrigerant control valve.

As compu_85 mentioned, cooling fan operation is based on refrigerant pressure, and if your RCV isn't letting the compressor load up, the fans won't come on. What you're experiencing is likely a symptom, and not the cause of your problem.

This thread from back in 2009 is the master RCV failure thread, and contains a lot of great information. http://forums.tdiclub.com/showthread.php?t=254699
 
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Stamie

Active member
Joined
May 20, 2010
Location
Long Island, NY
TDI
02 Golf GLS 324,000 all stock original..... 2013 Passat tdi se 62,000 same
Great info guys! Thanks for the help. Would pick up a Vagcom but not sure if I'll keep the Passat after the settlement is published. I need to read more about it but it all depends on whether we MUST comply with the fix or keep the car mapped as is. I love the performance/economy blend and wouldn't want to sacrifice that....too much.

In the meantime, I plan to borrow a VCGS to confirm and deploy a repair. Not urgent though since the Passat is my stand by and the Golf WORKHORSE just wants to keep on going while freezing me out in this hot muggy NY summer.
 

Stamie

Active member
Joined
May 20, 2010
Location
Long Island, NY
TDI
02 Golf GLS 324,000 all stock original..... 2013 Passat tdi se 62,000 same
Back again....good news?? this time. Problem disappeared on it's own. VCDS reads good all around. Probably a quirky RCV. just living with it for now until/IF it happens again. Thanks to all !!
 
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