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Grafted In The Vine
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Discussion Starter · #1 ·
Ok, I have spent hours reading through a lot of a/c issue posts. I have even posted on this in the past. Still, it seems that while some issues are similar, none of the suggested remedies are resolving my situation.

Main issue: 2000 1.8L a/c clutch will not engage. No power going to compressor. I pulled the power plug with the A/C control turned on with the car running, and tested both wires with a light circuit tester directly connected to the negative battery terminal. No light came on.

Low pressure line sits above 100. System recently evacuated and refilled by Eurocars. For $100, Eurocars diagnosed the dash a/c and heater control unit to be replaced, stating that there was a switch that is part of the control module but you had to replace the entire module($400+ including P&L), even though both my a/c and recirc plunger switches engaged and the lights came on. Blower works fine, too. I decided to buy two used ones off eBay from two different vendors (Cost effective at less than $50, plus, what are the chances that THREE would be bad) and did it myself. Still no compressor function or power.

Already checked:
Interior fuse panel OK
Battery fuse panel replaced by dealer in Jan 08 and OK
High Pressure switch jumpered and fans turn on OK

Could it be the fan control module? If so, why would the fans turn on when the pressure switch is jumpered?

Could it be the high pressure switch itself? I am thinking not since jumpering the switch engaged the fans, but not the compressor clutch.

I have read one suggestion in another post is to direct wire the compressor to the battery (hot wire?) to see if the clutch would engage. I know how to do a few things, and am willing to tinker, but unless it is spelled out for me, I get nervous. So, if this is going to be a suggestion (hako), please advise as to HOW to do this without blowing something up? :eek:

What am I missing? I would rather be able to test fuctions than start randomly replacing parts. Thanks in advance for any and all responses.
 

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Grafted In The Vine
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83 Posts
Discussion Starter · #2 ·
An interesting thing happened today...

Interesting, 45 views with no response. :confused:

Anyway, today was an interesting experience. I had on Saturday connected the electrical to the replacement dash a/c control unit. I had left the original connected to the cables. As stated previously, the a/c clutch never engaged and turned on. After testing the unit, I let the car sit in my garage and did not bother to put it back together. However, when I went to start the car prior to going to work today (Monday), the a/c immediately started to blow cold! Everything was working! I enjoyed a 25 minute cool ride to work. :D

Then, disaster struck.

I stopped at a store just before work. When I came back out and started the car, THE A/C DID NOT WORK !!! :banghead:

I do not know what I did other than start the car, turn off the car, and start the car again. Soooooo, I am going with a bad fan control module theory since I have read that they have a high failure rate, yet still get intermittent operation.

I am still open to further suggestion, and I will post the results of the install of the FCM when I get the part.
 

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No NB Yellow Trifecta :(
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The wife's NB ('00 1.8) started doing the same thing last week while we were on vacation. We were out of state so there was little I could do regarding any serious testing; however I did purchase a cheap R134 gauge kit and I monitored the pressure. When it worked the pressure was in around 25 to 35 and when it did not work it was a 100 or higher.

I also noticed that the car ran hot when the pressure was high; so I'm am not certain if the problem is caused by or the A/C system is simply reacting to some other problem.

Now I know both fans work, as they would both come on, especially if we were in stop and go traffic; while in city traffic I decided to perform another test. When the A/C fan came on I set the environment control to defrost, and then to maximum heat using fan position 2; the A/C fan would then turn off about two minutes after that and as long as I kept the defroster on the A/C fan would not come on; when I did turn the defroster off the A/C fan came on about minute later. So the A/C temp sensor and fan control module are working.

As of Sunday the A/C no longer works at all; how ever I still have issues with the motor running hot in stop and go traffic. No temp light ever came on.

When I come across the cause I'll let you know.
 

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Grafted In The Vine
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Discussion Starter · #4 · (Edited)
D2Beetle, thanks for the response. Maybe together we can resolve our like problems! I hate this for you, but I am glad I am not alone on this issue!!

I do remember reading in the VW Owner's Manual that when it is on defrost, the a/c is supposed to run. It was in the section on using the A/C and running it at least once each month during the winter to avoid drying out the seals. I tried this with mine and the compressor still does not run. I will try what you did with the fans, though. I am still thinking that there is a short in the FCM as the A/C worked for 25 minutes for the first time this year this past Monday. I have also read that there is an A/C relay somewhere under the battery tray. It is a $15 part at Autozone and looks like any other relay. However, I have yet to FIND that relay. Have you heard anything about said relay?
 

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There is a brown/red wire that goes to the aircon compressor magnetic clutch - apply +12v and this will engage the compressor over-riding the hi/low pressure switches etc etc. If you do this make sure the blower is blowing. This will only prove (if you get cold air) that the comp is OK and its an electrical problem. If it was me I'd figure a system to bypass the lot...maybe an on/off switch to the compressor....more than one way to skin a cat.
 

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Grafted In The Vine
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Discussion Starter · #6 ·
Hako, thanks for the response! Do you think a direct wire from the pos battery terminal would be a good way to test it? I may be tempted to run a bypass switch to the a/c compressor if I don't get this fixed soon!
 

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So long as you put a fuse in the wire! Also make sure you disconnect the factory wire that goes to the clutch so that +12VDC doesn't go back up the line! If the air then goes cold and you get no thumping from the compressor and stays that way for an hour or so then you'd have to presume the R134A refrigerant level is OK.
 

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Grafted In The Vine
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Discussion Starter · #8 ·
Ok, now it is going beyond the scope of "complication" for me. I am sure it is relatively simple, but as stated earlier, I don't want to blow anything up!
 

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Ok, now it is going beyond the scope of "complication" for me. I am sure it is relatively simple, but as stated earlier, I don't want to blow anything up!
When it comes to A/C problems they are always complicated and expensive; although I do use "alternative" repair methods in some cases, when it comes to A/C repair I do not.

Buying a moderately priced A/C refill gauge kit would be a better way to check refrigerant levels and you can use a light bulb tester to test the voltage to your compressor.

The relay panel is in the engine bay, drivers side, just to the left of the brake reservoir. It should be enclosed in a plastic housing.
 

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Grafted In The Vine
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Discussion Starter · #10 ·
Buying a moderately priced A/C refill gauge kit would be a better way to check refrigerant levels and you can use a light bulb tester to test the voltage to your compressor.

The relay panel is in the engine bay, drivers side, just to the left of the brake reservoir. It should be enclosed in a plastic housing.
Thanks! But, I am way beyond that point. Already used the light tester to determine no power to compressor, fuse panel on battery was replaced in January by dealer and verified still good, A/C refil kit with guage was the FIRST thing I did.

I have already taken it to a european general repair shop, but their recommended fix did not do the trick. I am going to do what I should have done in the first place, which is take it to an A/C specialist shop.

I will post the final fix after I get it back.
 

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No NB Yellow Trifecta :(
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Thanks! But, I am way beyond that point. Already used the light tester to determine no power to compressor, fuse panel on battery was replaced in January by dealer and verified still good, A/C refil kit with guage was the FIRST thing I did.

I have already taken it to a european general repair shop, but their recommended fix did not do the trick. I am going to do what I should have done in the first place, which is take it to an A/C specialist shop.

I will post the final fix after I get it back.
Lots of luck with the A/C specialist; I'm doing mine for the experience and budget reasons.
 

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Grafted In The Vine
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Discussion Starter · #12 ·
Lots of luck with the A/C specialist; I'm doing mine for the experience and budget reasons.
I can certainly understand the budget part. As for experience, while I do like to tinker, I certainly don't want to go "uh oh" and then have "a talk" with my wifey!! LOL :D
 

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Grafted In The Vine
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Discussion Starter · #13 ·
Final fix info as promised. Took a while. Just did not want to drive 100 miles to the dealer!!!

I had other issues which made it necessary to facilitate a trip to the dealer this past week. I had them do a diag on the a/c. They told me that the fan control module needed to be replaced. I thought that was interesting since I had replaced it myself and did not get any results. However, the service writer told me that the a/c was working and the techician said it was cold. They also said they would check the refrigerant level to make sure everything was topped off properly. $300 later, now it works. Actually, more than $300 if you consider the parts I bought and installed, the diag at another shop, et.al. Still.. just glad it is working. :) It gets hot in TN sometimes, and I am a whimp when it comes to hot weather!
 

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Sorry to hear about the extra dollars you dished out, but I did solve my problem after we came back from vacation; one of the three fuses on top of the battery melted away; fixed it and all is well.
 

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Final fix info as promised. Took a while. Just did not want to drive 100 miles to the dealer!!!

I had other issues which made it necessary to facilitate a trip to the dealer this past week. I had them do a diag on the a/c. They told me that the fan control module needed to be replaced. I thought that was interesting since I had replaced it myself and did not get any results. However, the service writer told me that the a/c was working and the techician said it was cold. They also said they would check the refrigerant level to make sure everything was topped off properly. $300 later, now it works. Actually, more than $300 if you consider the parts I bought and installed, the diag at another shop, et.al. Still.. just glad it is working. :) It gets hot in TN sometimes, and I am a whimp when it comes to hot weather!
so you'd finally replaced your fcm... how much you bought it... i think i have the same problem as yours... but there's only not the same is the wire going to compressor, i have current flowing there but its only 9volts... what went wrong buy that? i think may be the fcm too, because i already checked all fuses around except the relay and fcm... by the way, where is the relay located?
 

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A/C blues...

I hate to hear all these stories of New Beetle owners and their A/C problems. All modern A/C systems are extremely complex with VW's system even more than usual. There are many protection devices in our systems that protect the engine from over heating and protect the compressor from burning itself up. Everything connected to this series of fan relays with control units, pressure switches, temp. sensors and comfort modules is completely diagnosable with a VW VAG-COM scanner. A scan saves money by pinpointing the problem or problems the first time and then by only having to repair it once. That is if your VW service center has a competent mechanic that has VW training in VAG-COM. Just because a mechanic advertises foreign car repair does not mean that they can work on a modern VW with all it's magical computerized gizmotchery. Beware of non-VW mechanics... There are some that do good work but they are very rare. JK
 

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Same Problem

Final fix info as promised. Took a while. Just did not want to drive 100 miles to the dealer!!!

I had other issues which made it necessary to facilitate a trip to the dealer this past week. I had them do a diag on the a/c. They told me that the fan control module needed to be replaced. I thought that was interesting since I had replaced it myself and did not get any results. However, the service writer told me that the a/c was working and the techician said it was cold. They also said they would check the refrigerant level to make sure everything was topped off properly. $300 later, now it works. Actually, more than $300 if you consider the parts I bought and installed, the diag at another shop, et.al. Still.. just glad it is working. :) It gets hot in TN sometimes, and I am a whimp when it comes to hot weather!
Yea I have the exact same problem with mine!! I replaced the fan control switch and that did not fix the problem and also I checked where the relay is supposed to be in location 13 under the steering column and on my 2000 1.8 turbo the locations 11,12,and 13 are empty!! I then replaced the FCM and that still did not fix the problem!! the fans do not engage either. I know they work because I engaged the FCM relays inside the old FCM and the fans came on low and then hi when the other was activated. I can run a hot wire to the compressor and the compressor will engage and get cold so I know that the compressor is good. I hate to run a on of switch because I just hate to rig something like that!! What exactly did you say that the dealer replaced to make yours work because mine is doing exactly the same thing as yours was. Any advice is appreciated.
 

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Same Problem

Final fix info as promised. Took a while. Just did not want to drive 100 miles to the dealer!!!

I had other issues which made it necessary to facilitate a trip to the dealer this past week. I had them do a diag on the a/c. They told me that the fan control module needed to be replaced. I thought that was interesting since I had replaced it myself and did not get any results. However, the service writer told me that the a/c was working and the techician said it was cold. They also said they would check the refrigerant level to make sure everything was topped off properly. $300 later, now it works. Actually, more than $300 if you consider the parts I bought and installed, the diag at another shop, et.al. Still.. just glad it is working. :) It gets hot in TN sometimes, and I am a whimp when it comes to hot weather!
Yea when I checked mine with the A/C button pressed the wire coming out of the switch gets 12volts so I know that the switch is working on mine but it still will not activate the compressor clutch!!
 
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