About two months ago when I got out the car I heard a hissing sound coming from around the drivers side headlight. Shortly after I heard that I noticed my econ light was on and would not cut off. Well last week when I was working on the car I noticed the plug that attaches to the pressure safety switch was unplugged. I guess when I was adjusting my headlights I unplugged it and did not realize it. I plugged it back in and the econ light went off and only comes on then I press the button. Now my A/C does not get cold. Would a recharge fix it not being cold, or did that switch being unplugged damage something?
I dont think the plug would have caused something to go wrong but our AC condencers are make so flimsy that it would be hard to tell. I would go to your local auto parts store and try seeing if the system needs a fill. Its easy to do if you need more help just post here and I can walk you through it
Thanks. I may just buy a uv light. The dealer recharged it about 5yrs ago and they put dye in the system or so they said. Have you had your condenser replaced before?
Yes I had to replace my condencer before and im just if you ask jimmy who does a lot of maintenance work on these cars he would say hes changed alot of them as well. It is a part very prone to fail.
Try the recharge see what happens. There is a gauge on the recharge bottle letting you know what the system is at.
If you accidentally just drained the system, then chances are, you’ll be fine if you refill it. You were lucky enough to hear the hiss and know what you did to cause the leak, so if you put it back together without seeing what you’d consider damage, then you’ll probably be fine. I wouldn’t bother with the UV light yet.
If you refill your system, and then the AC works sometimes, but other times does not, then it’s your compressor sticking (it’s damn near seized). But if it worked fine before this hissing, then your compressor is likely still fine. Get your system recharged and take it from there. In the meantime, don’t turn on the AC until you get the system refilled.
How old is the car? Some of these Audi AC compressors only last like five years. Others last eight years. Not too many seem to see ten years.
I got one anyway for $12 with the glasses, just haven’t used it yet. I had zero issues with the AC until the plug came out and I had no unusual noises. I just heard a hissing sound when I parked the car and then the econ light stayed on until I noticed the disconnected plug a month and a half later. Plugged it back in and no light. Its an 04 I got it in 07.
I may just get it recharged on tues. I just wanted to try to trouble shoot before forking over money to get it charged and that doesn’t fix it. Does autozone or its competitors check AC systems with gauges?
I read through this thread. If you heard a hissing noise from below the driver’s side headlight then the first thing that I would want to check is that the AC high pressure switch is tight to the AC condenser. I see that you were calling it the pressure safety switch but I call it the AC high pressure switch. Just to be clear it is the thing that is plugged in about halfway up on the right side of the AC condenser in the below picture.
http://i284.photobucket.com/albums/ll37/Jimmybones777/SAM_0820_zps5jv523hi.jpg
Obviously don’t break the AC condenser end off by over-tightening the AC high pressure switch. I have done that before (even on my S4) and it sucks because then you have to replace the AC condenser too which requires taking the front bumper and a few other things off. The AC condenser has a shrader valve in it to stop leaks incase the high pressure switch has to be replaced. But if the switch is loose then the shrader valve could be open and leaking the refrigerant. At least you have a B6 S4 so that means that you can just take the driver’s side headlight out to get access to the high pressure switch. If you had a B7 S4 then you would have to take the front bumper off which is a lot more work than necessary for such a simple thing. One more reason that I prefer B6 S4s to B7 S4s.
Next if you have a vagcom then go into the 07-HVAC module and check the measuring value blocks. I forget which channel it is but go in order from channel 1 and eventually you will find a value that shows the AC refrigerant system pressure. Let us know what the pressure value is. I think that the minimum value is like 4 psi so if you see that then you know that you need a recharge.
It was fairly common for the AC compressors to crap out every 60K miles like clockwork on the B6 and B7 S4s. I have had to replace so many that I can do it in my sleep now. That includes two on my own two B6 S4s! If there is a good amount of system pressure for the refrigerant or if you get the refrigerant recharged and then the AC still doesn’t work then you likely need a new AC compressor. Here is a link for a quick overview of the replacement of a B7 S4 AC compressor that I did for my Jimmy’s Garage thread.
http://audirevolution.net/forum/index.php?topic=3781.msg109229#msg109229
Great advce to check the system pressure in vag com jimmy that will really help give a good idea on whats going on before going and paying any money to have anything done
I don’t have vagcom, but know I need to get one at some point. Yea its the switch right behind the headlight. I checked it tonight and didn’t see any dye, but that also doesn’t mean the dealer put any in there. I’m suppose to drop the car off and have it recharged on weds. They said that they would check it first and put dye in. If it turns out to be the condenser I would like to think I could change that myself. If its the compressor I’m sure I could change it myself in a week or two. If it turns out to be the compressor how good does this look for a replacement?
Holy crap I just seen the write up on changing the compressor. I would take me a year to change it. I am very mechanically inclined and I have done engine swaps in the past. This car honestly intimidates me and the fear if I do something wrong is up there. The shops that work on these cars down here are like an hr and half away and that’s my fear.
Everything on this car is harder then on most cars. The key is take your time and dont be afraid to take off more parts then less parts. The compressor sucks to change out and is hard even if you take all that stuff out.
Usually most shops are pretty good about testing and helping find the possible leak or dead compressor.
How long does the compressor typically take to replace? Also I don’t know if you had saw that link I had posted.
It takes me between 3 to 5 hours normally on a lift with air tools. Can take more time if things are really stuck from corrosion. I think that the book time is like 10 hours which is fair for someone that hasn’t done so many of them that they have all the different bolt/nut sizes memorized.
I tried your link and it didn’t work for me. Did a little searching and europaparts has a Nissens compressor listed for $399.95. FCP has the same Nissens compressor listed $352.11. Both are offering free shipping. Here is a link:
https://www.fcpeuro.com/products/audi-a-c-compressor-4f0260805ah
I have used the Nissens compressors before and they work. Did have one fail like a week after installing it though. The front half separated from the back half causing the AC refrigerant to leak out. FCP warrantied the compressor after the guy shipped back the bad one but he still had to pay for a second compressor plus labor in the mean time. Too many people have screwed the online stores so now they charge you for the second compressor and then refund the money when they get the old one back like a core charge for any normal brick and mortar store.
Yea those are the ones I was looking at… 10hrs wow. I hope I don’t need a compressor but I am preparing for the worst. I will let you guys know something one way or another tomorrow.
I did not get a chance to have the ac looked at today and may not be able to do it until friday. Can the high pressure switch be replaced without purging the system?
Yes, did it all the time.
Well took the car to have the ac looked yesterday and the tech was not there, after I was told he was going to be the day before. They told me to bring it back today. I get there today mind you I told them what I did and what the ac was doing since monday. They tell me that they can’t look at it because they need vagcom to reprogram the system to read the high pressure switch since I unplugged it. Now I know you need vagcom to do a lot, but is there any truth to that or did I get fed some BS?
Sounds like a line of BS to me. They are right that they would want a Vagcom to help but not for the reason they said
Well thats the last time I go to that shop. They have given me BS twice in the past 2 months.