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Jetta with AC problems Pages: 12

Luis G on Mon August 18, 2008 4:55 AM User is offlineView users profile

Year: 2006
Make: Volkswagon
Model: Jetta MKV
Engine Size: 1.9L TDI
Refrigerant Type: 134a
Ambient Temp: 90 F
Pressure Low: 140 psi
Pressure High: 140 psi
Country of Origin: United States

Hello,

The car's A/C just went from cold to warm yesterday, I took the readings after a long hot trip of about 200 miles. ( the engine was still hot)
Problem:
The compressor does not kick on. The LED on the ac button turns on and off when pressed. The inside blower works fine.
Along with the compressor, the condenser fans do not turn on. I tried to bypass the low pressure switch, but I could not. Not sure which two wires to jump.
The pressure switch has three wires on the plug. ( if this is the right one) lower left side on the low side hose.

The system should have enough pressure to kick the compressor on.
I have not checked the voltage to the compressor.

Any help on the switch would be great.

Thanks,

Luis

Edited: Wed August 20, 2008 at 10:22 AM by Luis G

TRB on Mon August 18, 2008 1:06 PM User is offlineView users profile

Might start with reading a few of these threads.

Jetta compressor issues.

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Luis G on Mon August 18, 2008 8:18 PM User is offlineView users profile

I have read all the posts that pertain to the Jetta. I will start checking out some of the sensors and keep the post updated as I go. I still would like some help on the pressure switch layout. And if I should try to jump it or not.


Thanks,

Luis

TRB on Mon August 18, 2008 8:59 PM User is offlineView users profile

Do not try and jump any pressures switches on this vehicle. Most important thing at this point is to now you have a correct charge level in the vehicle. This will require you to reclaim the refrigerant, pull a vacuum and recharge to the OEM specifications.

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When considering your next auto A/C purchase, please consider the site that supports you: ACkits.com
Contact: ACKits.com

Luis G on Tue August 19, 2008 2:54 AM User is offlineView users profile

By just looking at the low and hi side pressure that are in the system right now the compressor should turn on. What I need to know is how can I prove that one of the switches are bad, without having to buy and replace them. And if the compressor does not start with the current pressures now, how will it start by pulling a vac and putting a can on the low side?

If there is no way to check the pressure switch on this system other than to replace it, then that is what I will do, Just checking with you guys first to see if there was any other way.

both low and high side pressures were at 140psi. The engine compartment was hot when I checked it.

Luis

mk378 on Tue August 19, 2008 9:25 AM User is offline

The 3-wire devices are not switches. They are sensors that interact with one or more computers. You may be able to pull DTC's from the computer. First though check if the compressor is getting power to the clutch. (is this a clutch compressor, as some VW's used an electric variable compressor that is constantly engaged). If it is getting power it could be a faulty clutch or excessive gap.

Karl Hofmann on Tue August 19, 2008 10:06 AM User is offlineView users profile

The VAG.com diagnostic software is very good indeed for VAG vehicles..

As Tim has already said, don't go jumping switches or trying to send 12volts down a wire or you will toast something very expensive.. Without the correct diagnostic equipment on the electrical system then DIY is no longer an option

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Never knock on deaths door... Ring the doorbell and run away, death really hates that!

Luis G on Tue August 19, 2008 10:17 PM User is offlineView users profile

Thanks, I will check the voltage to the compressor in the morning. If I have no voltage to the compressor then what?

Luis

Luis G on Wed August 20, 2008 10:27 AM User is offlineView users profile

Well I checked the voltages to the compressor and they are.

8.8 VDC with the ac switch on and off -- with the engine off
10.2 VDC with ac switch on and off -- with the engine on.

compressor coil measures 11 ohms.

Condenser fans do not come on.

Thanks

Luis

Edited: Wed August 20, 2008 at 10:35 AM by Luis G

TRB on Wed August 20, 2008 10:35 AM User is offlineView users profile

Beginning to sound like a stuck or defective control valve in the compressor. Sometimes you can get them working again by revving the engine a little and or lightly tapping on the compressor with a hammer.

-------------------------

When considering your next auto A/C purchase, please consider the site that supports you: ACkits.com
Contact: ACKits.com


Edited: Wed August 20, 2008 at 12:18 PM by TRB

Luis G on Wed August 20, 2008 10:53 AM User is offlineView users profile



I tried it with no luck.

Just wondering why would the voltage be the same going to the compressor with the AC switch on and off?

Luis

Edited: Wed August 20, 2008 at 11:15 AM by Luis G

mk378 on Wed August 20, 2008 11:20 AM User is offline

11 ohms is not right for a conventional clutch compressor. Should be 3 or 4 ohms. Is this the electronic variable compressor? Does the wire go to the clutch under the pulley, or to a device in the side or the back of the compressor?

If it's the electronic variable compressor, the "clutch" in the front is supposed to be always "engaged". It is actually an expendable rubber coupling that is designed to shear away if (when) the compressor seizes so the belt doesn't break and disable the whole car.

Karl Hofmann on Wed August 20, 2008 11:56 AM User is offlineView users profile

The European Jetta diesel was fitted with a Sanden Clutchless compressor from 2005 so it could be a sheared clutch.. I have had a few fail for no apparent reason.



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Never knock on deaths door... Ring the doorbell and run away, death really hates that!

TRB on Wed August 20, 2008 12:31 PM User is offlineView users profile

Broken shaft could be a possibility also. Sanden 4573 is what should be on that vehicle.



-------------------------

When considering your next auto A/C purchase, please consider the site that supports you: ACkits.com
Contact: ACKits.com

Luis G on Wed August 20, 2008 5:51 PM User is offlineView users profile

Thanks for the pic. Tim and all the help guys,

That looks like the compressor body, but the pulley looks diff. the one on the car looks like a gold color.

The compressor power connects to the back of the compressor body.

If I let the gas out real slow and change the compressor, how much oil do you think I will need, or should I just flush it out and start new?

Thanks again

Luis.

mk378 on Wed August 20, 2008 6:24 PM User is offline

See if you can turn the center part of the clutch (the compressor shaft) freely. If the compressor has not seized you may have one of those "no apparent reason" ones that Karl mentioned and you can get it going again just by replacing the clutch instead of the whole thing.

Luis G on Wed August 20, 2008 6:54 PM User is offlineView users profile

The only things is, there is no center part to spin. the whole pulley spins together. I pulled the belt off and the pulley on the compressor spins very, very easy. Anyone know where I can buy one?

Thanks,

Luis

TRB on Wed August 20, 2008 9:03 PM User is offlineView users profile

Buy a compressor?

-------------------------

When considering your next auto A/C purchase, please consider the site that supports you: ACkits.com
Contact: ACKits.com

Luis G on Wed August 20, 2008 9:25 PM User is offlineView users profile

Yes a compressor, I looked on the web site and I could not fine one for this car.

TRB on Wed August 20, 2008 10:23 PM User is offlineView users profile

It's not listed but available. New compressor with clutch item number 20-08675 $ 353.00 plus freight.

I mention this agin, we have so many items that are not listed on the website! We are always adding new listings.

-------------------------

When considering your next auto A/C purchase, please consider the site that supports you: ACkits.com
Contact: ACKits.com

Matt L on Thu August 21, 2008 10:44 PM User is offline

May I ask how many miles are on that car? We have its brother.

Luis G on Fri August 22, 2008 2:42 PM User is offlineView users profile

We have 71000 on it. Only other problem so far was a front wheel bearing that went bad.

Luis

Luis G on Wed August 27, 2008 6:48 PM User is offlineView users profile

Turned out to be the high pressure sensor.

Thanks for the help.

Matt L on Wed August 27, 2008 10:40 PM User is offline

You're saying that your compressor did not fail?

Luis G on Thu August 28, 2008 5:03 AM User is offlineView users profile

Right the compressor did not fail. Looks like you need at least 12vdc to turn on the clutch. After I changed the high pressure sensor, the voltage to the compressor went to 13. I plugged the compressor back it and now it works like org.

Luis

Edited: Thu August 28, 2008 at 5:07 AM by Luis G

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