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Fans not working

Tiny
NASER NASER
  • MEMBER
  • 2008 VOLKSWAGEN GTI
  • 4 CYL
  • TURBO
  • 2WD
  • MANUAL
  • 215,000 MILES
I am sure the radiator fan comes on when needed but neither fans come on when I turn on the A/C. Compressor kicking, and it's cold only while driving. No overheating issue. Where are the fuses? I see a fuse box under the hood on driver side but nothing is labeled.
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Thursday, April 23rd, 2020 AT 9:29 AM

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Tiny
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Naser,

I attached two pics below showing the entire cooling fan circuit. There are two fuses that power the cooling fan module. I circled the fuses and highlighted locations.

Take a look through the schematic and let me know if it helps.

Take care,
Joe
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Thursday, April 23rd, 2020 AT 4:48 PM
Tiny
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Only two fuse boxes. I see one behind the small panel cover on left side of the steering, but there s no 50A fuse there. All smaller fuses and there is no fuse number 38 in that one. Says panel b but I don't see it.
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Saturday, April 25th, 2020 AT 7:31 AM
Tiny
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This.
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Saturday, April 25th, 2020 AT 7:31 AM
Tiny
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Found 38 in engine fuse box and its good, numbers 22 and 40 per the book show fan fuses one has a fuse and one doesn't both are 40a.I inserted the other one in the empty slot and both have power. Number 2 behind left side panel is one that someone has wired two fuses to take power from it I think it was for the aftermarket sound system, number 3 next to it is 5a fuse which the book shows nothing.
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Saturday, April 25th, 2020 AT 7:49 AM
Tiny
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Found fuse #3 by the battery, big 50a fuse, it's fine as well. Is there a way to activate the fan with the scanner? And if I did and they don't or do work, how to go about checking the module by the big fan? Which I see on the bottom of the big fan towards the driver side to see if it has power.
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Saturday, April 25th, 2020 AT 8:29 AM
Tiny
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I switched fuse 24 with 42 both 5a and both fans kicked on. Then after a minute they both stop. If I keep the 24 fuse off they both stay running.
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Saturday, April 25th, 2020 AT 8:44 AM
Tiny
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I see now that 24 controls the temperature gauge and fans go on because they don't know whether the car is hot, as soon as I install the fuse temperature gauge works and they both stop.
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Saturday, April 25th, 2020 AT 8:47 AM
Tiny
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Finally, after checking the wires, checked the connector going to the fans, has both negative and positive. Tried giving the connector a couple of pumps nothing happened, traced the wire going from the connector to the smaller A/C fan, which is behind the shroud, and gave it a couple of slaps and both fans worked. Checked Freon levels and it was decent, can you see if the gauges look okay? Driver side is not as cold as passenger but it is good enough, I added Freon and they are both cold bit not sure if it needs anymore. Also, why is it that all my gauges, whenever I disconnect them from the A/C ports they don't go back to zero, reset? How am I supposed to know what the new reading is if it doesn't go to zero and I go check another car?
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Saturday, April 25th, 2020 AT 12:59 PM
Tiny
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Hi,

If you open the valves on the tester once it is disconnected, it should release pressure in the gauge.

As far as the pressure is concerned. Is that static pressure? (AC off engine off)?

Let me know.

Joe
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Saturday, April 25th, 2020 AT 11:16 PM
Tiny
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No engine running and A/C on. Also when I turn off the car and come back next time to start it both fans off again. I have to it the connector for it to work. Does that usually indicate an issue with the fans or the connector?
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Sunday, April 26th, 2020 AT 12:52 PM
Tiny
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Removed the whole fan assembly, tried the connector by the A/C fan, its clean, I have negative and positive at the big connector at the radiator fan which supplies power to the A/C fan, but I only have positive at the A/C fan connector (with the car running and A/C on), no ground, so there could be an issue in wiring between the big fan connector and the small one?
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Sunday, April 26th, 2020 AT 2:22 PM
Tiny
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I attached a pic and circled the ground. It doesn't make sense you lose ground with it running and have it when it is off. Make sure that connection is clean and tight.

Joe
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Sunday, April 26th, 2020 AT 7:56 PM
Tiny
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No the ground I have is always there at the main fan, but I don't have ground at the smaller one which feeds from the main fan, whether car in or off.
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Sunday, April 26th, 2020 AT 8:12 PM
Tiny
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The control module provides the ground in that case. If you have no ground, suspect the module is the problem or you have a broken ground wire between the module and the second fan motor. Have you checked for that?

Joe
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Sunday, April 26th, 2020 AT 8:14 PM
Tiny
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I checked the connector and looks good, I guess check continuity between ground at main and ground at other fan?
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Sunday, April 26th, 2020 AT 8:19 PM
Tiny
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I feel that needs done. Naser, since neither fan works and you know the fan motors are both good, I have a feeling it is the control module.

Joe
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Monday, April 27th, 2020 AT 11:16 AM
Tiny
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But the control module is part of the whole assembly correct? Even though it can be replaced alone I believe. Some of the parts are rusty and what should I get as far as multimeter reading? Cause kn the positive am getting close to.1 negative 4.5.
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Monday, April 27th, 2020 AT 11:38 AM
Tiny
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If you are getting a -4.5V to the supply, something is causing power to back feed the wrong way. LOL Is that what you mean?

Joe
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Monday, April 27th, 2020 AT 12:04 PM
Tiny
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Here is a video:
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Monday, April 27th, 2020 AT 12:28 PM
Tiny
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I believe I'm looking at resistance. Is that correct? Here is the question: You have no ground which should be provided via the control module. If you are checking resistance to ground through the wire, that won't tell us why we lose ground when it is connected.

Please confirm for me.

Thanks, and sorry for all the questions. With everything disconnected as you have it, I just need to confirm what is being checked to be certain. I hope you understand.

Take care,
Joe
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Monday, April 27th, 2020 AT 8:10 PM

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