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I have a 2006 VW Jetta TDI (BRM engine). The fans are not running, and I would like to test the fans and the thermo-switch. I looked into the Bentley’s manual, but it doesn’t explain how to test the fans and/or thermo-switch. As a matter of fact, the manual refers to the thermo-switch, but it doesn’t indicate its location. Thank you for your help.
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The Radiator fan should be controlled by the PCM. The fan should be told to switch on by the PCM when the coolant temperature reaches a certain point. A quick way to test is to hook up a scanner and see what the PCM is being told the engine’s temperature is.
You may find you have an issue with a fuse, relay or wiring though instead of a switch…
JMHO
-Karl
Some VW’s have a fan control module box usually under the battery area. Not sure where on a Jetta it would be. (normally car makers tend to stay in the same zip-code for modules and such for all models)
If you have Air Conditioning and turn it ‘on’ do your fan(s) engage, or stay off?
S-
I’m not sure of the specifics on your model but you may find this information helpful.
http://www.ericthecarguy.com/faq/solving-automotive-electrical-problems
I also like to unplug the fans and power them up directly to see if they operate. In fact that’s often the first place I start when diagnosing cooling fans just so that I can verify their operation.
Good luck and keep us posted.
I don’t have an overheating problem. I want to test the thermo switch because the fans are not running when the air conditioning is on. Needless to say that I already checked fuses. My problem is that I cannot locate the thermo switch. Even when the Bentley’s manual talks about it, it doesn’t show its position. So what I need is to know where the switch is located. Thanks
Teddybear,
The fourth generation Jetta has the box you are talking about. It controls air conditioning and fans. The car I’m trying to fix is a fifth generation. That box is gone and according with the (Bentley) manual what makes the fans go is the thermo switch.
The air conditioning is not cooling well, evidently the condenser is not being cooled by the fans. I’m going to test the fans running a couple of wires directly, but I need to test the thermo switch also. It is the thermo switch location what I need. Thanks!Thank you Eric,
The specifics of my car are: 2006 VW TDI Jetta, engine size: 1.9 liter (BRM). I have the phone-book sized Bentley manual. It has the electric diagrams, it shows the thermo switch I want to test. It doesn’t show it’s location though.
What I did manage to locate (as I’m at work currently on break)
The thermo switch should be at the radiator itself. (according to another user with a 2009)
If you turn your A/C ‘on’ both fans SHOULD RUN regardless of what the thermo switch is doing. That makes sense, because your radiator is behind the A/C condense unit. The A/C will get a lot hotter then your radiator when it’s working–and with the thermo switch being located at the radiator itself? That’s for engine cooling, not the A/C.
That’s according to some information pulled from:
http://www.myturbodiesel.com/threads/air-conditioning-wont-work.6921/
Now all this info is well and good, you want to check your fans—Thermo switch looks like it should be radiator mounted. With the A/C turned ‘on’? The fan(s) should kick on regardless of engine temp.
It’s not quite the info requested, but it’s one way to see what the fans are doing.
S-
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