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Discussion Starter · #1 ·
My Daughters 99 beetle with the 2.0 has developed a battery drain and I thought I was starting to get it narrowed down. Last night I had .138A draw until I pulled fuse 43 then it would drop to .058A. At that point I was thinking cool now all I have to do is find a wiring diagram and go from there, well fast forward to this morning. I walked into my shop and the engine fans are running, fuse 43 is still removed. With lack of time this morning I just unhooked the battery and went to work. Since I am very new to Volkswagen and haven't had the need to acquire a service manual I am flying somewhat blind.

My question at this point is what would be a common cause for the fans to run with key off engine off.

Since I am new here a little about myself. I am a farm machinery service technician at a CaseIH dealership with 25 years of experience. I primarily work on combines (harvest machines), planters and tractors. I specialize in electrical systems including precision ag, all the fancy GPS stuff.
 

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Discussion Starter · #3 ·
Thank you, I checked for published recalls but nothing applied to this problem. I haven't had a chance to get back to diagnosing this thing but will soon.
 

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Your problem may not be the fan control module. Fuse 43 is for the ECU, so you probably should see a drop of .05 or .06 amp when removing this one. It could be that with the ECU powered down the fan controller got confused and turned the fans on. The fans on these cars can run with the key out if the radiator is still above the temperature setpoint. The power to the fan controller is always present.

I would continue trying to chase down the source of the missing .08 amps that still remains. Here is my DIY on parasitic drain in the New Beetles.

http://newbeetle.org/forums/questio...0356-how-test-parasitic-drain-new-beetle.html
 

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Discussion Starter · #5 ·
Okay I had some time to work on it tonight. What I found is with everything connected and key off the fans run. When I turn the key on the fans run even faster. The engine temp according to my scanner is 59 deg F. I found the fan control module and right by it screwed into the radiator is a 3 pin sensor. When I unplugged this sensor the fans shut off. I looked at Napa online and found this sensor but I think the pins are round instead of a blade type. I will have to look in the morning, I didn't have my glasses on. Looks like I will need to get another adapter for my vacuum radiator fill tool.
 

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Discussion Starter · #7 ·
My vacuum radiator fill tool is from Mac Tools as well as my radiator pressure tester. The farm equipment I work on I only need 4 adapters and 3 of the 4 came in the kit.

Good news! Problem is found and fixed, I hope. The fan control sensor that is in the left tank of the radiator toward the bottom had failed. This caused the fans to run with key off and run full speed with the key on. When I unplugged the sensor the fans shut off.

Hopefully this helps someone else.
 

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Discussion Starter · #9 ·
There was a code but I'm pretty sure I caused it by unplugging sensors.

It sure is nice to finally have all my vehicles running properly for a change. All 4 cars and my truck, nothing needing attention for now. Tonight I can get the tire chains on my tractor and clear the snow off of my driveway!
 
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