# Radiator Fans not working



## leeq61 (Apr 20, 2007)

Guys some help as always would really be appreciated please.

Ive recently had my thermostat, coolant temp sensor changed due to problems with the temperature gauge which i now suspect as Dashpod failure and its going in for a diagnosis on Thursday to Warrington Audi. Ive noticed now that my radiator fans have stopped working, so today i replaced the radiator temperature switch (triangular shape) after pulling the plug and testing that my fans still work by connecting 12 volts to them.... as soon as i did the both fans started to spin. Now ive been out for a run and done the 49C check and my engines gets up to 97 - 100 degrees and still nothing with the fans [smiley=bigcry.gif] the small external aterrun pump works fine after i switch off the engine and does what its suppose to do for about 10mins, I just have no sign of life from the radiator fans and im worrying that my engine may overheat on long runs. Does anyone have any ideas what this could possibly be. My cambelt waterpump etc was changed at 60,000 miles in Oct also.

Any help would really be appreciated.
Thanks


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## leeq61 (Apr 20, 2007)

Ive just checked and all the hoses seem full and hot, i dunno if that helps but any suggestions or help would be great


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## skai (Feb 29, 2008)

Hi!

Check the fuse to the left (I think) on top of your battery. Green 30A if I remember correctly.


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## Cris (Jan 5, 2009)

Make sure your not running your climate control on "econ" mode. when "econ" is switced on, the fans dont normally cut in until engine temp gets to 102c/103c. where they bring the engine temp down to 95c/96c and stop. when you are running your climate control on "auto" the fans should be constantly running at a low speed if the outside temp is greater than around 5c. From reading other posts on here it seems that common reasons for fans not working are dead fuses underneath the batter cover, faulty low speed fan resistor's, dodgy fan switches.........


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## daveyboytt (Sep 5, 2008)

mine did this last week i changed all the green fuses on top of the battery and next to these is a fuse distribution plate with fuses bolted down the 40 amp one is for the fans mine had blown changed this and now all is fine


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## Nick10 (Jan 28, 2009)

mmm im having same probs, I have smaller fan operating,but not large,car stays at 90 idling, but once i get to a steady 80-90 or above(kilometers) the temp guage rises to alarm and overheat? , i stop and in the time it takes to get seat belt off it has cooled to 90 again.also the air con goes hot in the overheat period?

really confused, had new thermostat and green heat sensor thingy?it is in audi now but theyre a bit baffled at moment?

any suggestions anyone,will check fuses when i get it back later also?

really frustrated no being able to drive my new toy,which is 180 BHP FWD TT 2003 with only 45k on clock, fully audi servided from new and imac car,i have done 100 k so far, bought private so no come backs ??im sad?

please help, desperate now?

Nick.
( i am also in australia,not that that matters does it)


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## kite (Sep 3, 2006)

Nick10 said:


> mmm im having same probs, I have smaller fan operating,but not large,car stays at 90 idling, but once i get to a steady 80-90 or above(kilometers) the temp guage rises to alarm and overheat? , i stop and in the time it takes to get seat belt off it has cooled to 90 again.also the air con goes hot in the overheat period?
> 
> really confused, had new thermostat and green heat sensor thingy?it is in audi now but theyre a bit baffled at moment?
> 
> ...


Sounds like you have a broken water pump...........


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## Nick10 (Jan 28, 2009)

yeh suspecting that now, Audi now have it ,so should find that

any more info anyone??

Nick.


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## Nick10 (Jan 28, 2009)

ok audi claim they have found burnt out relays, that operate the main fans, and the fans wernt operating at all, they are replacing the fans(burnt out)and the relays back to fuse box?they say that will sort it?

hope so $1400 australian dollars?


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## Audi-Sport (Jan 2, 2009)

I currently have the same problem - and again audi have said they want to replace the main relay and both fans.. £320 worth of parts alone! I just can't help think audi only want to replace parts and not diagnose faults - so they blanket change all possible parts costing you and I a small fortune!

Hmmmm, what to do now - as I'm not splashing out the ~£560 audi are after to do the job!


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## Nick10 (Jan 28, 2009)

hey audi sport,

well ive given go ahead, and they tell me that will fix the problem, the way i see it, i have no choice,i suspected the water pump, they says its not,what can i do, i have a 40 grand (dollar) sitting here not working that i fear to drive,

will let you know if its solves problem.

keep those pommie fingers crossed for an aussi in toruble,


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## John-H (Jul 13, 2005)

Audi-Sport said:


> I currently have the same problem - and again audi have said they want to replace the main relay and both fans.. £320 worth of parts alone! I just can't help think audi only want to replace parts and not diagnose faults - so they blanket change all possible parts costing you and I a small fortune!
> 
> Hmmmm, what to do now - as I'm not splashing out the ~£560 audi are after to do the job!


Of course it's hot over there isn't it? We're all sued to it being cold and so you wouldn't need the fans on whilst cruising as there would be enough airflow through the radiator. Hense the thought that it must be the waterpump. If it's really hot outside you may need fan assistance even if driving though.

What puzzles me is you saying that after it overheats and you stop it cools down. If the fans were not working I'd have expected it not to cool down because there is no airflow.

I'm wondering if what may be happening is that only your aircon fan is working and that's not creating enough airflow when you drive as it won't be full on all the time depending on your temp settings etc. and so your engine overheats as it's not turning on its main fan. But when you stop the aircon fan's airflow is enough to bring the engine idling temperature down.

If that's correct, you only have one suspect fan, not two, and the problem may only be that the fuse needs a clean :wink: Be careful of this fuse - when it gets a bad connection it can get hot, melt the fuseholder and even cause a fire. I'd replace this first and test the fan independently - there may be nothing wrong with it!


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## Nick10 (Jan 28, 2009)

Thanks John, yeah its 40 plus C this time of year,the air outside is hot air from tropics,as i live east coast north of brisbane,.Audi have run 4 days of tests and investigation and say the relay and fan are burnt out,they have ordered parts and i have no choce but to go ahead,im just keeping my fingers crossed this is it,cause if Audi dont know who does?

keep you all posted

Nick.


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## Nick10 (Jan 28, 2009)

aaaarrrrg

well after $1293.95 australian dollars,and the fans now all working, they decide its the water pump after all,and of course when you change water pump, you do the cam belt etc also,another $1100.00 coming there way,its friday now, so 2 dead days till they order the pump, may see car wednesday and a bill for arround $2400.00,

Audi!!cough cough, , maybe ill get a KIA.

bread and water again for dinner tonght.


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## Audi-Sport (Jan 2, 2009)

Interesting as my car has the same fualt - yet my water pump was replaced only a year ago and double checked by Audi last week..... If your fans are not working they are not working - this will not be caused by the water pump. (I don't think?)

However, if your fans are all working correctly then yes it could be your water pump on the way out that is causing the car to run hot has my other halfs Golf GTi 1.8T was doing just this when her Water pump was on the way out. The problem with mine appears to be that the 1st low speed fan is not cutting in when the engine gets warm - and only the second fast fan works. So, I'm going to test the fans tonight with a mechanic mate and I hope I find one of them is not working correctly. If they both are the block like module under the battery (£78+vat) will be my first point of call. Then if that doesn't sort it - god knows!


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## Nick10 (Jan 28, 2009)

mmm,i am fairly convinced it is the water pump in my case,i will keep you posted, is yours hot at idle or just running?

mine was ok at idle,the small fan enough to cool,but at speed im guessing the pump just doesnt pump no more?impeller spinning on shaft maybe.


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## Audi-Sport (Jan 2, 2009)

My running temperature in fine in all conditions (90c) until you push the 'econ' button in and then the temperature starts to rise - but the low speed fan didn't start operating so the main fast fan has to cut in and out erratically doing all the work! Also, the fans don't operate when the air-con is switched on!

So, check the fans tonight with 12v as I'm hoping one of those will be nakered - then if not the large relay.. :-|


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## Nick10 (Jan 28, 2009)

update,

finally got car back fixed, ended up water pump, but had cam belt changed at same time, also had the fan(large) and its controller replaced,thermostat,and heat(green)sensor.

so $3488.00 australian later.

all good as new again, now to sell it and get a KIA

Nick.


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## Audi-Sport (Jan 2, 2009)

WOW - thats a big bill!
I've bought a 2nd hand set of fans for £75 and I'm hoping they will turn up today and we can fit them next week. Fingers crossed as I don't want a bill like yours!

Glad your all sorted now though - enjoy it 8) (the car that is - not the bill!)


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## daveyboytt (Sep 5, 2008)

thats a huge bill i had pump and belt changed for $700 australian christ mate u got robbed $3488 is over £1.5 kin the uk no more shrimps on the barbie for a month or two hey mate


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## Trippin (Jun 15, 2009)

i just had the exact saem symptoms, and exact same wrong diagnosis of waterpump

turns out it was the fuse that burnt itself and a section of the casing - and the garage wants to replace both fans as "they caused the burn-out by drawing too much current" ? ? ? not sure about this...

£550 to replace both fans and the fuse casing - ive just paid £580 to replace track rods and 2 shocks, only had the car 6 weeks and im beginning to really regret buying it especially seeing as ive just been told clutch is slipping 

just wanted to see if anyone had gone through the same thing and had any advice to share...


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## Hoggy (May 8, 2002)

Hi Trippin, Hasn't happened to me, but someone on forum has reported fuses & housing on top of battery melting & catching fire IIRC. Caused by corrosion & poor connection of fuses etc. Hopefully replacing fuse housing etc will cure your prob. Quite a high amperage connection, so a poor connection will cause lots of heat.
H.


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## Trippin (Jun 15, 2009)

Harold said:


> Hi Trippin, Hasn't happened to me, but someone on forum has reported fuses & housing on top of battery melting & catching fire IIRC. Caused by corrosion & poor connection of fuses etc. Hopefully replacing fuse housing etc will cure your prob. Quite a high amperage connection, so a poor connection will cause lots of heat.
> H.


thanks very much Harold - i just tried a few other words in the search and ran accross a great thread on this issue from Morgan with photos of exact same problem etc


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## hoss (Feb 17, 2010)

+1 for this solution.
My AC and cooling fans failed on the same day. First green fuse has got hot and had a bad contact.


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## crono35 (Dec 27, 2013)

I have a very similar condition. Low speed fans never turn on, even with new fan control module, new fan temp switch, new water pump, etc.

I'll regularly see 105* on 49c, even if it's only 80* f ambient. I never overheat when moving, only when idling. My AC doesn't work, so hitting econ doesn't help. I've tested both fans by providing 12v directly and they work on both low and high speed. I've sent 12V directly to both fans via the fan pigtail and they both work properly.

At this point I'm probably going to remove my AC (don't want to deal with it anymore, and this is a toy car primarily) and replace the radiator. I'm wondering if there's a buildup of crap between the condenser and radiator that may be blocking significant airflow... still doesn't explain why the low speed fans don't turn on though. I've read here and elsewhere that the low speed fans don't run, and that no fans run until 102/103 unless the AC is on, but that doesn't make too much sense to me, considering the fan switch is supposed to run at 95*c.


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## John-H (Jul 13, 2005)

What happens when you short the loom contacts at the thermostatic switch on the radiator?

Also, is your aircon clutch working?


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## maltloaf (May 8, 2015)

I went through quite a lot of this trying to diagnose my air con problems.

You can prove slow speed operation by shorting pins 1 and 2 on the radiator thermoswitch, which is usually located near the fan control module which on my 180q is under the battery. Slow speed fans can run completely independently of the air con and fan control module and without the ignition being on, just when the temperature goes high enough.

￼If the slow speed fans don't run with that shorted, check fuse S180 which is a standard type blade fuse, 30A, on top of the battery especially including the connection of the fuse to the terminal underneath which has a history of melting.

Fast speed fans are controlled via the FCM. You can test the fast mode fans in much the same way as above but the ignition needs to be on to power the FCM, air con off (econ lit) and you now short pins 2 and 3 on the thermoswitch.

Fast speed is fed from 40A fuse S164, again on top of the battery which in this case is a bolted down metal link.

Diagnose your fans first. If you get them running then look at the FCM or AC system.

I'll include a diagram which I found really useful in case it's any help.

S501 is the thermoswitch.

My fault turned out to be a broken wire which meant the fan control module never got it's power. The slow speed fans would still run when the engine got hot enough but neither fast nor the air con would work.

Good luck 

malty


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## crono35 (Dec 27, 2013)

Is there a way to test the fans from the fuses on top of the battery?

I was able to get my high speed fans to run by providing 12v and ground to the fan switch, but not low speed.


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