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Where are we at with the coolant flush, water pump impeller check; then, refill and burping the system or just vacuum fill, to remove any air pockets? The fans typically, will not kick-on; if there is air in the cooling system. Beyond that, i would confirm all the speeds for the fans work (low speeds are known to burn out); then check the fan switch and the cooling fan controller.
 

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OKAY SO I finally got that radiator fan off and brought it over to autozone to test it, bc I'm the dumb ash that took it out to test it instead of learning how to test it from inside the car. Anyways the fans are fully functional and work just fine.

So what's the problem? What do I do next.
Current goal is to get these fans to spin inside of my car. The fuses are fine and replaced as well as the fuse box, the fans have no electric or mechanical problem, what's the next thing for me to test?
Have you tried replacing the fan control module itself already? Also did you check fuse 5 on the side paneling by the door? it's a 7.5 amper and I believe it provides power to the fan control module and inside the car blower fan light. It might also provide power to the high pressure sensor for the A/C system.
 

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Where are we at with the coolant flush, water pump impeller check; then, refill and burping the system or just vacuum fill, to remove any air pockets? The fans typically, will not kick-on; if there is air in the cooling system. Beyond that, i would confirm all the speeds for the fans work (low speeds are known to burn out); then check the fan switch and the cooling fan controller.
I'm not sure that's 100% billymade because the radiator itself has a high temperature sensor mounted on it that turns on the fans directly first at low then at high speed. There is a 2nd sensor mounted on the coolant flange by the fire wall and that turns on the fans via the ECM and the FCM. Then there's a third temperature sensor on the 1.8t cars mounted by the front on a 3 way "Y" hose connection for the third speed which only the large fan has but both fans come on at top speed.
 

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Discussion Starter #24
I have flushed the coolant and refilled it with the pink stuff, and no I have not checked the fan control module. How would I go about diagnosing that that is the issue? Should it be giving off certain readings?

I still need to check the water pump, but the coolant seems like its flowing fine, but after a 10-20min drive the coolant is HOT like bubbling and it was below 40 out.

The car only overheated towards the end of that drive and when I drove it back home I drove it super easy and it didn't overheat.

None of the fans of course turn on, at all or make any attempt to. The light for the AC button doesn't come on either

But anyways I dont think my coolant is the problem. I think my car is just for some reason not able to turn the fans on. It could be any number of the 3 to 4 thermostats/coolant temp sensors or whatever but even still the AC should come on when the key is in. So now I guess my money's on that switch being busted.

If anyone can provide more information on that, that would be helpful.
 

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I would confirm, the water pump is 100% good, as they can spin on the shaft, it can be confusing , as it works ok, then not cool adequately under load, when driving at higher speeds. Next, that there is no air in the cooling system; a vacuum filler tool will eliminate any air, you can rule that out quickly. The 1.8T in particular, can be hard to burp the system; air in the cooling system, can cause it to overheat.

These two issues, have been problems on the mark iv volkswagen; since they came out and especially, when the stock composite plastic failure prone impeller stock water pump is installed. These two issues need to be confirmed and do not assume they are ok, without checking them.

Beyond that; here is some service manual info for the fan control module:

 

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Have you tried replacing the fan control module itself already? Also did you check fuse 5 on the side paneling by the door? it's a 7.5 amper and I believe it provides power to the fan control module and inside the car blower fan light. It might also provide power to the high pressure sensor for the A/C system.
I'm just curious, you said blower fan light, is that the light that illuminates the switch on the dash? That light is out on my dash. Thanks
 

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I'm just curious, you said blower fan light, is that the light that illuminates the switch on the dash? That light is out on my dash. Thanks
Yes. That fuse 5 provides power for that dash light fresh air recirculating fan plus also goes into the FCM for what reason I don't know, maybe just a signal. Also provides voltage to the dash air circulating servo motor & the A/C high pressure sensor. Well in my car's schematic it does. 1.8t. Fuse 25 provides power to the A/C light switch on the dash, blower resistor pack and the blower speed knob.
 

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Yes. That fuse 5 provides power for that dash light fresh air recirculating fan plus also goes into the FCM for what reason I don't know, maybe just a signal. Also provides voltage to the dash air circulating servo motor & the A/C high pressure sensor. Well in my car's schematic it does. 1.8t. Fuse 25 provides power to the A/C light switch on the dash, blower resistor pack and the blower speed knob.
Thank you for the info. I will definitely be checking that tomorrow.
 

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There is also a bulb in the panel with the HVAC controls. Pull the fan control knob out and the bulb is there.
 
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