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AC Compressor Question

1067 Views 7 Replies 3 Participants Last post by  janitz
I've got a question that I can't seem to find an answer to. I've got a 2002 Turbo S. The AC compressor runs constantly. I mean that even when the AC switch in the HVAC controls is disengaged, the compressor still runs, the clutch never disengages the compressor.

I read somewhere this was a problem with the fan control module, I have no idea where that is or if it's even a part actually on my car. I also can't seem to find it listed on any parts house website.

I was thinking maybe the switch in the dash was just bad or possibly maybe the clutch is just stuck, not likely but possible I guess. So does anyone have any idea what's causing this, is there an FCM on these cars and could it be the problem?
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The fan control module acts as the relay for the A/C compressor, so it definitely could be the problem. See this thread for all the information you ever wanted to know about the fan control module:

Wow, what a ton of information and a lot of sensors and modules going on… wow.

So, I have also noticed that I don't hear or feel that aux water pump working either. I certainly don't hear my fans doing anything after the car is switched off. I'll have to verify tomorrow whether the fans are doing anything at all… but at least now I have something to go by and something that'll tell me what to check and what to expect.

This is my first VW. I have to say this is the absolute coolest little car I've ever driven but it seems more complicated than what I came from (Mustang).:D
If it is not very hot outside and you haven't driven the car hard I don't think you'll have the radiator fans running.

Here in Canada I rarely hear them running, it's only when it gets into summer and the temp is above 80 F that I'll hear my radiator fans run unless I turn on the AC.

Before I fixed my AC last summer the only way I could tell if my fans were still able to run was by jumping the connection to test.
Thanks for that input. I haven't checked anything yet. Nothing past knowing that the AC compressor runs even with the AC turned completely off inside the car. I'm not sure about the fans yet, the warmest it's been around here so far this year has been 70. And I'm pretty positive the aux pump isn't working, I don't hear anything at all from under the hood when I switch the car off. Maybe that's due to the temp's like you say about the fans… I don't know yet.

Honestly, I bought an 86 GT Mustang to restore before I bought this Bug. The Bug pretty much made me forget the stang… but lately I've been trying to get that thing put back together so I can get it out my garage, my Bug needs a cubby to park in :D

So maybe here in the next week or so, I'll get off my asphalt and check my precious little Bug.
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I'm not sure what could be causing the AC compressor to continuously operate like that. Usually the issue is that it won't turn on.

How have you determined that it is running, maybe by visual inspection and you can see the triangle plate on the clutch spinning when the engine is on and stationary when it is off?

I'm not sure on the 1.8 where the compressor is on the accessories arm, on my TDI it is at the bottom and easy to access from under the car. On mine I would simply crawl under and disconnect the electrical on the compressor. That would stop it from running at least, might be a good idea if you can reach the thing.
With the engine running, AC controls OFF… it's engaged and running. I haven't checked to see if it's engaged while the engine is off though. I haven't tried to unplug it yet either. It's been rainy here and I've got my garage piled full, so I can't put my Bug in there right now to be able to check it.

I need to. I'm finding lots of little things that this car needs, nothing major (yet). But it's to be expected, it's a 2002, not a 2012.
My 98 is like that too, many old and wearing out parts requiring a good deal of attention to keep in operational condition. It is now to the point that I am buying a new car to be my primary vehicle and the Beetle will be kept in the garage and tinkered with and driven for fun.
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