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DGAFxxx
03-16-2007, 07:10 AM
I bought my car over the winter, so I wasn't able to test the AC when I got it. I have put it on 64 and low, but it doesn't seem to blow really cold air. The air is cool, but not like it should be. Is there something else I can do to make sure it is working correctly before I get a recharge?

Ewok_Fetus
03-16-2007, 01:02 PM
Scan codes in your A/C system...

http://www.audiworld.com/tech/int6.shtml

Find out if you threw any codes... If not, make sure your compressor is kicking in... Just turn the car on at idle with a/c off, then during idle, turn on the compressor with the econ button. The car will bog for a second and the secondary fan should kick in also. If it does not, I would say it is either a fuse, relay or your MAF possibly...

bOOOOstedAudi
03-16-2007, 01:05 PM
may just need a drain and fill of R134

Ewok_Fetus
03-16-2007, 01:09 PM
may just need a drain and fill of R134

If he scans for codes and gets one for R134 low pressure switch tripped, then I would say you could go that route... But I would scan for codes first as that is a free diagnosis...

bOOOOstedAudi
03-16-2007, 01:15 PM
If he scans for codes and gets one for R134 low pressure switch tripped, then I would say you could go that route... But I would scan for codes first as that is a free diagnosis...

LISTEN TO THIS GUY...




















hes right.

Ewok_Fetus
03-16-2007, 01:19 PM
Of course!! I am always right!! Hahaha, just kidding man... I am wrong some times but I will always admit it... I have my own way of doing things which involves doing the easy stuff first!!

bOOOOstedAudi
03-16-2007, 01:22 PM
Same as me. I dont know a lot but somethings I do know. I hate when people try to pull your card because you asked advice or something.

DGAFxxx
03-19-2007, 07:01 AM
I ran the diagnostics via the climate control, and also did a scan with the VAG. So far no errors showing on either. I popped my hood and was trying to make sure I could hear the clutch on the ac compressor engage. Didn't sound like it was doing that, so hopefully I can figure it out. If not I guess I'll just try a recharge and see if that works.

Ewok_Fetus
03-19-2007, 07:59 AM
If a recharge doesn't help out, pull the passenger side headlight and there will be the pressure switch on the condensor. Pull the plug off and take a small piece of wire and put between pins 1/2 on the wire harness. If the compressor does not kick on again, then your problems lies elsewhere other than needing a refil. Also, go ahead and try pins 3/4 on the harness. 1/2 is your low pressure and 3/4 is your high pressure. Also, check to see if you have your 12V between pins 1/2 and 3/4. But actually before all of that, take a DVM and remove the green connector that is on the fan assymbly to see if you are getting 12V there. This is the signal to engage the clutch. Do you have a CEL at all? Because like I said before, on my 2001, the MAF causes my A/C to crap out. I don't know if that is a DBW thing or just a 2001 thing. If you need anymore help at all, let me know!! Also, if you are ever under your knee bolster where the relays are, check the relay at the very top of the relay cluster. Should be a white relay, if it is red, then you have an outdated relay... I think they are $20 but any normal 4 pin relay should work in that position...

Ewok_Fetus
03-19-2007, 08:01 AM
The part number on the relay should be 443 919 578C FYI...

DGAFxxx
03-19-2007, 08:35 AM
yes I do have a CEL, the CEL is due to both 02 sensors going bad, I've been meaning to fix them, but if that could be directly related to my AC I will try that now.

Ewok_Fetus
03-19-2007, 08:43 AM
Hmmmm, I know a bad MAF COULD throw off a code for bad o2 sensors for some reason... Those are the only two codes? None for Secondary Air Injection system, incorrect flow or anything? Low MAF signal? I don't know why it would throw a code for those when it is a bad MAF but that was my case!! I had three major codes thrown until I replaced my MAF.

MAF singal too low
SAI incorrect flow
Secondary o2 sensor something or other...

I am not saying this is your problem at all, but at least places you should look towards... Before you start throwing parts at it though hoping to fix it, look into the above procedure...

bOOOOstedAudi
03-19-2007, 08:45 AM
443 919 578C, A/C Clutch Relay 25 SHIPPED

DGAFxxx
03-19-2007, 12:11 PM
Ewok, I'll post the codes later after I get home and Vag it. But I am getting a few 02 codes... also I do get the secondary air injection code quite often coming up. Maybe my MAF is bad and not my 02 sensors?

Ewok_Fetus
03-19-2007, 12:16 PM
ECS has them for $19.95 plus shipping... Also, like I said, you can just use a regular SPST Automotive relay I am sure. They would be about $5 at autozone...

Ewok_Fetus
03-19-2007, 12:26 PM
Okay, another thing to do here if you do have the correct relay which you should. Take off the knee bolster on the drivers side. Find the A/C clutch relay and remove it from its socket. Take a reading with the car on, across terminals 85 and 86. Make sure your A/C is "ON" and car running... If you do not get 12V at those two points, then the signal is not comming from the head unit. Now, take a jumper wire and connect to terminal 30 and 87. Enjoy the cold air comming through!! Jumping 30 and 87 will bypass everything and will MAKE your A/C engage... I wouldn't run it like this forever though... Just use it as troubleshooting.

I am just trying to throw out as much stuff as possible here for you to look at before you say you need a top-off... Especially since you haven't thrown any HVAC codes...

akielb
07-22-2007, 02:39 PM
OK - I'm bringing this one back up since I'm having the same problem. only difference is that I have a 1998.5 1.8TQ
I cannot access the HVAC module with my vagcom "too many errors"
I tested the 40amp fuse and its not blown but it also didn't have any power going threw it. I found the A/C clutch relay #443 919 578C with #267 printed on it. I pulled it and wrapped a wire around 30 and 87 and put it back in - I then had cold air. Aux fan is still not running at all, but spins by hand. How would I test to see if the fan is getting power? where does the fan harness plug into? is there a way to test the relay?

Hoping this is just a relay, oh and if it a coincidence or not I installed a new HID kit last night and then the fan/ A/C didn't work anymore.

Ewok_Fetus
07-22-2007, 03:14 PM
Try to scan your system with the above link that I provided in the 2nd post.

This 40A fuse, where is it located. How do you know it doesn't have power going through it?

Also, do both speeds not work on the fan? Should have a low and high speed.

Did the fan come on when you jumped the relay?

Do you have access to a multimeter or at least a voltmeter? Let me know and I will help you out as much as possible...

akielb
07-22-2007, 04:46 PM
Try to scan your system with the above link that I provided in the 2nd post.
OK I will try that - assumed that was for a MY 2k and not me

This 40A fuse, where is it located. How do you know it doesn't have power going through it?
The 40A fuse if located behind the knee bolster, and is attached to the bottom of the 8-way Relay carrier. If you have a Bentley there is a diagram on page Y 321 of the electrical area.
I turned the car on and put a voltmeter on it and grounded the other lead from the volt meter. No power.

Also, do both speeds not work on the fan? Should have a low and high speed.
The fan is not on at all - does not rotate when car is on - I can physically move it so I know its not stuck on something.

Did the fan come on when you jumped the relay?
No

Do you have access to a multimeter or at least a voltmeter? Let me know and I will help you out as much as possible...
yes, I have one but I have very limited knowledge on how to use it.

Thanks for your help

Ewok_Fetus
07-22-2007, 05:20 PM
Pics removed for ease of loading and we already found answer!

akielb
07-22-2007, 05:36 PM
#1
any way to help me

Ewok_Fetus
07-22-2007, 05:39 PM
Since you are #1, you are correct, you cannot scan unless you have a vag...

Okay, we will start out with your 40A fuse issue. You know the terminal blocks on the relay panel, should read 75X, 30, 30, 30a or something like that... Turn the car on and see if you have power to either of the 30's... This is the main power to your fan. It supplies the power for both the low and high speed.

Not saying this is you or anything but make sure also, that your voltmeter is on the correct setting... Meaning use the V-DC setting and not AC. I have seen a few times someone using the AC setting on DC circuits. VDC is a V with --- over it. VAC is a V with a ~ over it...

akielb
07-22-2007, 05:53 PM
ok all have power 75x, 30,30,30

Ewok_Fetus
07-22-2007, 06:07 PM
ok all have power 75x, 30,30,30

Now, remove the fuse, turn car on and check both contacts of the fuse holder. One should have 12V and the other should not... Also, when the fuse is out, make sure it isn't a dead fuse... Put it on the OHM setting and measure one side of the fuse to the other.... Post up your results!!

akielb
07-22-2007, 06:16 PM
ok - I have power from one contact and not the other - I put the meter on the Ohm setting and when I put one lead on each prong of the fuse I get 0.00. I plugged the fuse back in and I now have power on both sides of the fuse - I must have not been pushing the lead in hard enough or something.

akielb
07-22-2007, 08:58 PM
Is there a way to test the A/C clutch relay? would that be the next step?

Ewok_Fetus
07-22-2007, 09:19 PM
Is there a way to test the A/C clutch relay? would that be the next step?

Yeah, you could do that... Take it out of the car, attach the multimeter to pins 87 and 30. Take a couple of jumper wires and energize the relay by jumping pin 86 to ground and pin 85 to +. I don't think this is going to be your problem at all. Another thing to test is to see if you are even getting an output from your climate control panel at all.

How to test that...

Make sure the A/C relay is removed... Start the car and make sure the a/c is set to "ON" so that the compressor would normally be on... Set the multimeter to OHM again and measure from a GOOD KNOWN GROUND to where pin 86 would go if it were in the relay slot... It should read 0 OHMS or close to it since that signal is shunted to ground... You won't be able to read a voltage since that is comming in from 85. Also, you could make sure that where pin 85 is supposed to be, that you are getting 12V there...

If you don't read 0 OHMS when you measure pin 86, then you are not getting your a/c on signal from your climate control panel which means a few things...

Outside temp sensor is faulty
High or Low pressure switch has been tripped
Could need a top off of R-134
Bad sunlight sensor

akielb
07-22-2007, 09:21 PM
Will do it first thing in the morning - Thanks for all your help - going to get this bitch figured out eventually

Ewok_Fetus
07-22-2007, 09:32 PM
Hahaha, yeah. I took three days of troubleshooting my car, had everything torn apart... I mean EVERYTHING that had to do with the A/C... Any covers or anything that had any wire going through them so I could inspect and what not... Everything was good but my shit still wouldn't turn on... Then one day my MAF came in the mail that I was waiting for.... Guess what, that fixed it... But that is a DBW thing...

akielb
07-23-2007, 10:17 AM
ok - I measured the 85 and 86. with the car running and the a/c on I didn't get near zero ohms from 86. I do get a power reading from 85.

is there a way to test these

Outside temp sensor is faulty
High or Low pressure switch has been tripped
Could need a top off of R-134
Bad sunlight sensor

Ewok_Fetus
07-23-2007, 10:24 AM
Okay, so we have figured that your head unit is not putting out the signal...

What does your outside temp display read? If it isn't way off like reading -40* on a hot summer day or something like that, I then doubt this is your problem...

You can check the pressure switches with your ohm meter... However, I am not sure where they are located on your car...

Sunlight sensors usually do not go bad, I don't think this would be the problem...

Best bet would to charge up your system somehow... Depends on how you want to do it... Take it to a shop or DIY... They have refill kits at auto parts stores... Don't know if you use R12 or R134a either... Probably R134a but you do NOT want to mix the two... Also, if you do find it is R134a, make sure you get the refill kit that has the oil in it...

That is my recommendation is to charge up the system though... Probably tripped your low pressure switch and the control panel tells it not to turn on to save the compressor...

akielb
07-23-2007, 10:47 AM
What does your outside temp display read? If it isn't way off like reading -40* on a hot summer day or something like that, I then doubt this is your problem...
no my outside temp sensor reads 85 right now and that is close to what it is supposed to be. It has on occasion when I first start it up read somthing like -63* but that went away every time within a few minutes of driving and hasn't happened lately

You can check the pressure switches with your ohm meter... However, I am not sure where they are located on your car...

Sunlight sensors usually do not go bad, I don't think this would be the problem...

Best bet would to charge up your system somehow... Depends on how you want to do it... Take it to a shop or DIY... They have refill kits at auto parts stores... Don't know if you use R12 or R134a either... Probably R134a but you do NOT want to mix the two... Also, if you do find it is R134a, make sure you get the refill kit that has the oil in it...
Just called my local dealer and they verified R134a, so I guess I'll try that. Any Idea how much I should be charged for a refill kit? I made an appointment for tomorrow at 2:00, but if I can figure it out myself then I will just cancel.

That is my recommendation is to charge up the system though... Probably tripped your low pressure switch and the control panel tells it not to turn on to save the compressor...

Thanks for all your help.

Ewok_Fetus
07-23-2007, 10:52 AM
Okay, I have also had my display read some off the wall measurement and I removed the head unit and unplugged all connectors and plugged them back in... Display went good... You can try that... Also, maybe about $15 for the recharge kit... Get one with the gauge on it... Read the directions on the can carefully as they will tell you the correct way to do it... But if you are going to go ahead and make an appointment for them to fill it, I would do it that way so they can properly purge and fill the system...

akielb
07-23-2007, 11:46 AM
I ran to the auto parts store and I purchased a can of R134a with a gauge tester on it. I was already over(+) were the gauge said I was good to go almost 100lbs of R134a. So R134a pressure is not the problem. Dam, I thought that was going to be it.

Ewok_Fetus
07-23-2007, 11:50 AM
I ran to the auto parts store and I purchased a can of R134a with a gauge tester on it. I was already over(+) were the gauge said I was good to go almost 100lbs of R134a. So R134a pressure is not the problem. Dam, I thought that was going to be it.

100 psi is way over the top...

I am sorry, this is what you should try...

Jump the relay like you did before to make the compressor come on... This part is cruitial and is probably why you were getting like 100psi...

Make sure the compressor is going and the fan is turned all the way up and try again...

akielb
07-23-2007, 12:28 PM
Here are two parts

#1 - I jumped 30 and 87 to make the A/C come on and I tried it again - It wasn't as high this time - I filled it to about 45lbs where it was it was max ok. How did I verify that the compressor is running? I don't hear anything, just nothing and then the blower starts to kick in with cold air. Aux fan is still not doing anything.

I just got back up here from doing what you said earlier about testing the relay

"Take it out of the car, attach the multimeter to pins 87 and 30. Take a couple of jumper wires and energize the relay by jumping pin 86 to ground and pin 85 to +. I don't think this is going to be your problem at all. Another thing to test is to see if you are even getting an output from your climate control panel at all."

I did this and I didn't get any power coming through the 30 and 87. what does this mean?

Ewok_Fetus
07-23-2007, 12:42 PM
Okay, techinically you should not be seeing ANY "power" comming out of the relay... A relay is nothing but a mechanical switch that is normally off in this situation... When a current is passed through the coils of the relay (pins 85 and 86) a magnetic field draws the switch to a closed position... When this relay is open, you should read OL (overload) or not get any reading or deflection of your meter... When the relay closes you should be getting 0 ohms in a perfect world... This is between the pins 87 and 30... Hope I didn't confuse you much...

In this drawing I just made up, the batter is hooked to 85/86 and the multimeter to 87/30. Like I said, all you are doing is testing the funcion of the relay here...

http://members.cox.net/baldwin4/powa.JPG

akielb
07-23-2007, 12:52 PM
ok - i did that and I get an ohm reading of zero - when I disconnect the power I get nothing.

Ewok_Fetus
07-23-2007, 12:53 PM
ok - i did that and I get an ohm reading of zero - when I disconnect the power I get nothing.
Awsome, that is how the relay should be working...


Okay, lets also move on to the fan problem... I want you to check also a fuse for the signal power to turn on your fan... It is the one right next to the 40A fuse you pulled earlier... Right of to the left of it... Should be a 5A fuse... Check that fuse to see if it is good... If it is good we will continue on to the low speed relay...

I am assuming you have a Bently from earlier comments you made... On the 8 way relay carrier, pull out relay #3 and short pin 30/87 together... This is a high current fan so only leave it on there for a second to see if the fan comes on... You don't need the motor running to do this, so just have the ignition in the on position like the motor is running. What do you get now?

Try the same with the relay in position #2... What about now?

If the above here work like they are supposed to, then I would say you need a new coolant temp sensor...

akielb
07-23-2007, 01:10 PM
5amp fuse is OK
relay #213 in #2 position when jumped the fan turns on - key did not have to be in the on position
relay #214 in #3 position when jumped the fan turns on - key did not have to be in the on position

Ewok_Fetus
07-23-2007, 01:26 PM
Ah, yes you are correct, I read the diagram wrong for a second... Terminal 30 doesn't need the key on for power, 75X does and I read it comming off of 75X... My bad... So, in all reality your fan is good... Did you notice if position two sounded like a higher speed than position three? Position 3 had a resistor in place that drops voltage to create a lower fan speed. When position 2 kicks in, it has no resistance therefore causing the fan to kick in at full speed... However, it sounds like maybe your fan control sensor is possibly bad? This seems to be the only other thing it could be... Maybe it isn't connected at all?! Do you have a 1.8 or 2.8?

akielb
07-23-2007, 01:38 PM
1998.5 1.8t quattro tiptronic.
Wasn't really paying attention to that, but yeah I think #3 was louder than #2

I want to test the high and low pressure switches. I've located the high, which is located behind the front bumper and just under the headlight. But I can't seem to locate the low. any idea where that one is located? here is picture of its location from AESIS
http://i142.photobucket.com/albums/r85/akielb/lowpressureswitch.gif

How would I go about checking these switches?

Ewok_Fetus
07-23-2007, 01:44 PM
191 959 481C sounds like the part you would need... It is the coolant fan switch as I stated before... Don't quote me on this... I am not trying to spend your money for you, but it all kinda makse sense... Another thing I guess you can do to test this is to jump the wires at the switch connection... Here is how to do that....

Turn the key to the ON position but do not start! Make sure your car is in gear or in park and the ebrake fully engaged...

Jack up the drivers side and please use a jack stand... I have had a buddy of mine die from his head being crushed under his car just because he was going to be under there for "Just a second."

On the driver side you have an upper and lower radiator hose... On the lower hose about 4 inches away from the radiator should be an electrical connector going to your fan control switch... Remove the connector from the switch and bring it down to where you have enough room to make a jump or two... Should have three pins in there...

On the electical connector, pin 3 is your ground and 1 and 2 are your low and high respectivly... Jump from pin 3 to 1. Does the fan come on? What about pin 3 to 2? Should come in with a high speed... Let me know what you find... If it works here, then it should definatly be your switch... We have tried everything else... Don't forget too that this fan only comes on with the A/C (which isn't turning on by the way so the fan will not kick on until you resolve that.) AND it also comes on when you reach high coolant temps... I think the low speed kicks in around 85-95 degrees C and the high kicks in at 90-100 range...

I just want to make sure that your fan is working properly... LOL it would really suck having me make you do all this troubleshooting just to find your car isn't getting hot enough to kick the secondary fan on... So just to verify that, you sure that the fan doesn't kick on when your car is up to temp?!

Ewok_Fetus
07-23-2007, 01:49 PM
1998.5 1.8t quattro tiptronic.
Wasn't really paying attention to that, but yeah I think #3 was louder than #2

I want to test the high and low pressure switches. I've located the high, which is located behind the front bumper and just under the headlight. But I can't seem to locate the low. any idea where that one is located? here is picture of its location from AESIS
http://i142.photobucket.com/albums/r85/akielb/lowpressureswitch.gif

How would I go about checking these switches?

How many pins does the one behind the headlight have? 2 or 4? If it has two then the low pressure switch should be under the cowl next to the fresh air filter for the cab... If it has 4 pins then this is both the high and low switch... When you test the high pressure switch, test to make sure a voltage is comming out of the connector and the switch should read OL or the ohm meter should not move... The low switch should also have a voltage going through the electrical connector and the switch itself should be reading 0 OHMS... These tests should be done with the compressor jumped like previously so your A/C is blowing the cold air...

akielb
07-23-2007, 02:35 PM
Yes, I just warmed up the car to normal operating temp and I still have no A/C and the fan is not moving, outside temp said 97 - I have an underground garage, so the car is cool when I get in it - the blower starts off low then slowly as I'm driving around starts to blow harder and harder trying to cool the cabin.

I pulled the elec connector and I jumped each wire with #1 and I get 1 high and one low - fan comes on so does that for sure mean that the switch is bad?

Ewok_Fetus
07-23-2007, 02:40 PM
It is a pretty good indication... We have tested EVERYTHING that would make the fan not come on... Both the relays, the power going to the fan relays... The thing that makes the fan come on however is a different story... Like I said, I am not 100% but if it was my car I would change it... I just don't want you to buy something and not be the problem... Where does your temp gauge sit when driving and it is up to temp?! Does it ever go past the middle line at all?

akielb
07-23-2007, 03:05 PM
well that switch is 58.15 at my dealer (2 blocks away) so I guess I'll have to order it online from ECS for 12.95 - lol, I'll check the high and low tonight sometime.

Ewok_Fetus
07-23-2007, 03:20 PM
Cool... www.worldimpex.com has it for $10... I like worldimpex a little more than ECS but that is just personal opinion...

DGAFxxx
07-23-2007, 03:22 PM
It is a pretty good indication... We have tested EVERYTHING that would make the fan not come on... Both the relays, the power going to the fan relays... The thing that makes the fan come on however is a different story... Like I said, I am not 100% but if it was my car I would change it... I just don't want you to buy something and not be the problem... Where does your temp gauge sit when driving and it is up to temp?! Does it ever go past the middle line at all?

this sounds like the problem I had on my car. I finally got sick of troubleshooting with no results and no AC that I just hard wired my compressor. I unplugged the clip at the bottom of the compressor, sliced in a wire, ran it inside the cab, hooked it into the fusebox, and wired a switch in line. Now my compressor kicks on since I am forcing power to it, and my AC blows super cold.

I only plan on using this as a temp fix until I can figure out what it is. Ordered a new MAF sensor, hopefully it should be here tomorrow, and I'm curious to see if it fixes my problem.

Ewok_Fetus
07-23-2007, 03:57 PM
Hey, DGAF, didn't I help you out just like this too?! LOL!

akielb
07-23-2007, 05:23 PM
does the fan switch not working(if its not working) have anything to do with the A/C not kicking in? Or is that a totally different problem?

on the temp sensor, I'm leaving for a weeks vacation on thursday so I'll make the order some time next week so that it will get here right when I get home. I won't have time tonight to remove the bumper and test the high pressure switch, but I might be able to find the low if I get out there and start looking for it. thanks for your help

akielb
07-23-2007, 05:37 PM
another quick question about the sensor

Click here for search (http://www.worldimpex.com/search_by_partno.html?searchmode=partno&partno=191+959+481C&x=37&y=8)
there are two listed when I search the part number above at the site you suggested. one is "102-91" is 10.50 and the other is 75c is 14.33 - both list 191-959-481-C as the mfg part #. is there a difference or is this just a "brand" thing

DGAFxxx
07-23-2007, 05:41 PM
Hey, DGAF, didn't I help you out just like this too?! LOL!

Yes.... haha not long ago...

finally got around to ordering a new MAF sensor... maybe that will fix it... if not, oh well... my AC blows cold the way I have it rigged up now....

akielb
07-25-2007, 10:26 AM
well, I think this is bad. I needed to go pick up my wife for lunch, so I jumped the A/C relay to make the compressor work. she works only one block away and I drove there and sat in the parking lot for no more than 5-8 min. All of a sudden I hear a loud whooshing should and there is a white could coming out from under my hood. I turn the car off immediately and jump out to look - I can see kind of a white markings on the ground in front of the car and there is water leaking from the bottom of the car(likely just condensation). I pull the A/C relay and start the car. Do you think that I blew the compressor? or was this some kind of emergency relief valve giving out?

Ewok_Fetus
07-25-2007, 10:30 AM
There is a high pressure valve that opens at like 500psi on the compressor... Not too sure why it would have done that though...

akielb
07-25-2007, 10:34 AM
I just found this thread HERE (http://www.audizine.com/forum/showthread.php?t=57013&highlight=A%2FC+cloud) sounds like the exact same thing. I shot him off a message we'll see what he comes back with.

link corrected

akielb
07-25-2007, 08:35 PM
He said he never got it fixed, and then the car was totaled. he still thinks that it was the compressor that failed.

Ewok_Fetus
07-26-2007, 12:57 PM
Hmmm... I actually have another thing for you to test to make sure it isn't the A/C pressure switches... But now you may have depleted your R134 so can't do it until you figure out that problem... But one thing to check is unplug the low pressure switch, jump the connector on the harness, unplug the high pressure switch... Try to turn on the car and run the A/C... You are bypassing the switches now and compressor should turn on if this is your problem... Only do this if you are certain that there is still R134 in the system...

akielb
07-27-2007, 06:04 PM
I will do that as soon as I get back from vacation. I just got done driving 1300 miles down to TX. I'll be back 8/6 and get right to workin on it.

Ewok_Fetus
07-28-2007, 04:30 AM
Hahah, damn dude!! Stop by OKC on your way back and maybe I can help a bit!!

akielb
07-28-2007, 11:01 AM
yeah - that would have been great - lol

went through OKC about 9am on friday. going back through Colorado, and we're drivin the wifes Sentra, that would have been a hell of a trip with no A/C

Ewok_Fetus
07-28-2007, 11:36 AM
Hahah, I gotcha!! Hope you had fun comming through this hell hole!

akielb
08-08-2007, 10:35 AM
Hmmm... I actually have another thing for you to test to make sure it isn't the A/C pressure switches... But now you may have depleted your R134 so can't do it until you figure out that problem... But one thing to check is unplug the low pressure switch, jump the connector on the harness, unplug the high pressure switch... Try to turn on the car and run the A/C... You are bypassing the switches now and compressor should turn on if this is your problem... Only do this if you are certain that there is still R134 in the system...


I was looking at the wrong MY earlier when I said I thought I had two separate low and high switches. 97+ has the all in one switch. here is a diagram of it
http://i142.photobucket.com/albums/r85/akielb/AChighlowswitch.gif
I jumped #1 and #2 - nothing changed - I turned the ignition to accessories and the A/C did not turn on. I also checked the plug for power and Ohm reading. I did not get any power with the car on and the ohm did not give a value(unchanged) when I touched #1 and #2. Am I supposed to have the relay jumped?

akielb
08-09-2007, 07:49 AM
Any Idea's

Ewok_Fetus
08-09-2007, 06:01 PM
Okay, did you refill the system yet? Just to make sure it isn't completely gone? Also, did you jump the connections on A or B? You need to do them on B... 1 and 2 should always be a closed circuit... Also, you need to jump 1 and 2 when the car is running... You do not need the relay jumped for this... But if you DID check 1 and 2 on the "A" connection and it read OL (overload) or no deflection on the gauge, then you need to top off and try again...

akielb
08-09-2007, 07:29 PM
Yes I did it on the B connector not the sensor itself. I jumped 1 and 2 on B and started the car - this did nothing. are you saying that I need to start the car then jump the connector 1 and 2?
I jumped the relay and hooked up my A/C charge kit to the charge port and it said almost 60lbs of pressure. when I jump the relay I can still get some cold air but not like before. Is there a way that I can empty the system and refill it, just to be sure? (sine R134a is not harmful to the atmosphere)

I also did the ohm and power test on the B connector. should I have gotten any kind of reading from that connector?

akielb
08-14-2007, 08:33 AM
Any more help would be greatly appreciated!!

akielb
08-25-2007, 08:19 PM
well, I finally got my aux fan temp sensor in the mail and found time today to install it. Guess what. Didn't change a FUCKING THING!! - I'm getting so pissed at this damn A/C - guess I'm just going to end up bringing it in. Not sure when that will happen, no money to waste on it right now. Maybe if the weather was a little warmer I would care more, but its almost fall. Won't need the a/c much longer anyway, guess it will be something that can be dealt with next spring. Thanks to ewok_fetus for all of his help. I'll come back when ever I finally do get this all fixed and update to what exactly it was.

akielb
05-29-2008, 01:42 PM
Took it into the shop and had them look at it. Tech says that its my High/low pressure switch. So I'll replace that.

anyone know the part number for this switch on my car? otherwise I'll search around tonight.

mab9981
05-13-2010, 07:58 AM
For those that said it was the MAF sensor, did the ac work if you disconnected it?
I have a 96 a4 2.8 quattro with similar problems.
The condesner fan and the ac wont turn on, however both work if they are directly powered. I tried another CC unit and that didn't solve the problem and i replaced the ac clutch relay.

As far as check engine light, i've had one on for a little bit, (don't remember what it was) and the idle isn't as steady as i would like it. Wondering if i could unplug the MAF and solve all my problems at once?

akielb
05-13-2010, 09:10 AM
Wow - I haven't had A/C for a long time.

Tech spent a few days playing with different things a couple weeks ago. Still can't pinpoint what the problem is. Still getting a pressure switch short to ground error after replacing the switch.

Ewok_Fetus
06-04-2010, 03:07 PM
Akielb... I would start searching for shorts in the wire harness.

Mabb... I only know of the DBW cars having the signal go through the MAF. So I don't think yours has a MAF/AC issue...

a4_1.8t_01
06-04-2010, 07:06 PM
Why are you guys making him check all that. If there is no refrigerant the compressor will not come on. All you need is a recharge. Thats why it blows cooled. If there is a leak then it would explain why its low.

Ewok_Fetus
07-17-2010, 08:03 AM
Why are you guys making him check all that. If there is no refrigerant the compressor will not come on. All you need is a recharge. Thats why it blows cooled. If there is a leak then it would explain why its low.

Read the post from the beginning... It was explained to do a re-fill / top off a couple of times before we got into the diagnostic portion...

akielb
07-17-2010, 07:31 PM
Replaced HVAC unit.....nope. Didn't help. Not sure what I'll do. Not sure if I'm up to start searching for a short(or know where to start).

imtimmy
04-15-2013, 09:12 PM
3yrs no AC after all the troubleshooting? Just read through the posts on this thread and was hoping for a good outcome. I have a '06 A4 that AC has not been working over a year now. I'm determined not to go another Texas summer without AC. I had 3 shops look at my car last summer and all told me the compressor was bad. I'm not entirely convinced however and kinda think they just wanted me to let them do the big costly job. 2 of the shops actually did tell me the compressor turns on but something is preventing it from blowing cool air. Fans work, heat works, refrigerant was checked and was full. After reading here and some other posts elsewhere I'll try the pressure switch, clutch relay switch? I have priced compressors for awhile now, new from about $340 and I found a used one for $200 near me in Dallas. Just would like to know for sure it's not something else before buying a compressor.

ianwpb
04-15-2013, 09:49 PM
3yrs no AC after all the troubleshooting? Just read through the posts on this thread and was hoping for a good outcome. I have a '06 A4 that AC has not been working over a year now. I'm determined not to go another Texas summer without AC. I had 3 shops look at my car last summer and all told me the compressor was bad. I'm not entirely convinced however and kinda think they just wanted me to let them do the big costly job. 2 of the shops actually did tell me the compressor turns on but something is preventing it from blowing cool air. Fans work, heat works, refrigerant was checked and was full. After reading here and some other posts elsewhere I'll try the pressure switch, clutch relay switch? I have priced compressors for awhile now, new from about $340 and I found a used one for $200 near me in Dallas. Just would like to know for sure it's not something else before buying a compressor.

Waking the dead huh?


Anyways, If you want to check if your compressor is functioning you could always jump the A/C compressor relay. I'm not sure if it's the same on a B7 as it is on a B5 though.

On my B5 I just pulled the driver side knee panel to expose the relays. Find your A/C compressor relay. It was number 267 on my car. Remove the relay and use a jumper wire (small section of wire with male spade connectors attached). On the B5, terminal 30 was sw/bl 2.5 (12awg) and terminal 87 was gn/ge 2.5. If this causes the A/C compressor to turn on and blow cold, then you know a component that gives a signal to that relay is not functioning correctly. This basically bypasses the pressure switch by supplying power directly from the Load Reduction Relay to the A/C Compressor, instead of using a signal from the pressure switch to allow the compressor to run. Try it out.

By the way, you may have more luck in the B7 section.

imtimmy
04-16-2013, 12:59 AM
Haha! exactly, waking the dead. Been searching different threads here and some other forums just trying to get ideas of the more likely causes given my scenario. I will definitely try out the compressor relay, I can't tell if the compressor goes on at all. When on auto mode it will heat well, recirculation button lights, econ button lights, defrost works, blower working. Is the compressor to turn on only in "auto" mode? Despite the other modes functioning there is still never cold air put out.

akielb
04-16-2013, 04:53 AM
Wish I had something better to add after all this time. I ended up selling the A4 about 2 1/2 years ago without ever getting it fixed. Good luck.

walky_talky20
04-16-2013, 06:15 AM
Haha! exactly, waking the dead. Been searching different threads here and some other forums just trying to get ideas of the more likely causes given my scenario. I will definitely try out the compressor relay, I can't tell if the compressor goes on at all. When on auto mode it will heat well, recirculation button lights, econ button lights, defrost works, blower working. Is the compressor to turn on only in "auto" mode? Despite the other modes functioning there is still never cold air put out.

You should definitely consult the B7 forum. The AC compressor on your '06 is completely different than our B5's. It is a "variable displacement" compressor. So there is no "relay" that "kicks on" on the compressor like our simple little B5's. It is a completely *variable* control from the AC control head. It is not and "on" or "off" situation. It is a more complicated system.

If they are telling you the compressor is bad, it could be just the variable displacement control solenoid itself that has failed. Usually these solenoids can be changed separately, however due to the aluminum construction of the compressor, they are often badly corroded and thus impossible to extract. You can test for continuity across the 2 pins at the compressor. If that is good, you can check for the control voltage at those pins (backprobe the pins with engine and AC on). The higher the voltage, the higher the cooling request. If it's getting control voltage, but the system pressures are not changing, then you can determine it to be a failed compressor or failed solenoid. The shops you took it too may have performed this testing already - I can't know. In any case, a junkyard compressor with 6 month warranty is probably your cheapest option at that point.