Audi TT Mk1 Overheating 🔥 1.8t radiator fan not working properly. What to check DIY guide 🔧

I can't believe how close i am BUT there's something tripping me up. The radiator fans on the Audi TT Roadster Restoration aren't working properly at all. I've done a few heat cycles and each time the radiator fans aren't working. Sad. Is this something you're looking to fix?
Luckily there are several things you can try to find what your issue is. I go through most of the common tests and finally find my issue (but i can't believe i did what i did!)
00:58 Pulling #16 fuse test - simplest test to do that helps you see if there's an issue with your low speed fans
1:54 Supplyying direct 12v power overview - this test helps you determine if there are wiring or low speed fan relay issues
2:32 Testing radiator fans at low speed
3:37 Testing radiator fans at high speed
5:03 Fan control module swap and inspection
7:25 Inspecting thermostat (DOH!)
7:58 final radiator fan tests
I'm happy to get myself out of this pickle and hope the video helps you out too. (If you have an Audi S3 8L , VW Golf Mk4 or Bora you can use this troubleshooting guide as the setups are pretty much identical).
- Ian
Follow me on Insta
/ auditt3.6
PART NUMBERS
Large fan - 6X0959455F / 6X0959455A / 1J0959455F
Small fan - 1C0959455C / 1J0959455M
Fan control module - 1J0919506K, 1J0919506Q

[@ianpgonzaga]

Hands up if this is something you have come across? Let me know if this helps!

[@ianpgonzaga]

@@tindraxx7226hi! cable thing?? In what part sorry?

[@ianpgonzaga]

@@tindraxx7226 oh that's just a spare wire with spade connector on the end. You can easily get those things from a hardware or electronic component shop for a few dollars.

[@c0wsg0m00]

just noticed mine are not working, wont even spin up with the aircon. Going to try these steps tomorrow at work. this guide was great, earned a sub from me.

[@ianpgonzaga]

@@c0wsg0m00 thanks 🙏 hope this helps you get to the bottom of things (and that it's not a silly thermostat install mistake like I found out haha)

[@King_Of_Sparta_]

Hi, brilliant video, Thanks you . I find your videos informative , helpful , clear and concise. Keep up the great work. Well done .

[@ingojohansson7996]

I pulled fuse 16 and both fans run. But I did the cable on the pins test and nothing work. I replaced both fans, all sensors, fusebox, and control module. Now what? :(

[@stevesloan6775]

That was a really decisive and to the point video, with informative screen graphics. I will be trying to workout why my fans aren’t working on my mk1 TT today. It’s also a plus that you’re an Aussie! Happy Australia day!! 🇦🇺🤜🏼🤛🏼🍀🍀🍀☮️😎

[@ianpgonzaga]

Hope you can get to the bottom of things! Happy Aus Day 🇦🇺🦘 and looong weekend!

[@elielsandunguero]

What is the fuse 16 name? Thx great video by the way.

[@ianpgonzaga]

Should be #16 10A Radiator fan control unit

[@georgioskaragkounis8476]

Hey! Nice job! I have a TT front wheel drive with 180 horsepower! I ve change the thermostat and the water pump my small fan isn’t working alive only when the big one works. And then I have 110 degrees on the dash after the fans are engaging it drops to 90. Is the FCM?

[@ianpgonzaga]

@@georgioskaragkounis8476 yeah definitely replace the FCM.

[@jedbarrett4658]

Hi how do I get that display up

[@renedewael9703]

Hi ! Just did the tip to test the fan, with a cable between pin 1/2 and 2/3. All is good ! I’m 99% sure that my overheating come from the thermocontact, since on idle the fans never spin. And I have replaced the calorstat a few days ago. Gonna change it this week end. Very great tip ! ;)

[@ianpgonzaga]

Good luck and hope the video Helps!!!

[@mp-ez1it]

I’m exactly same situation fan work on 90c don’t work if ac open… if remove fuse 16 work both also high low speed work if I connect wires what I’m need? Relay and thermostat like u?

[@ianpgonzaga]

Try them first because they are cheap 😜

[@mp-ez1it]

@@ianpgonzaga im thing iys thermoswitch after thermoswitch all work i will try thermoswitch and thermostat with colant change im not sure if its right mixed

[@FREDINHOOO7]

Hi, great video, I am having the same issue with my car, I replace my Radiator switch, new control module, new relays, new water pump, tested with new, thermostat, without thermostat, new headgasket for the engine, car is still running hot, the car fans turn on, when activate the AC,but never auto when car is overheating, I have no fckngggg idea waht to do anymore, any idea???

[@ianpgonzaga]

Sounds like you've been having some fun herre ;) Replacement of the fans sounds like will be next thing to do.

[@FREDINHOOO7]

I am going crazy this morning windows are not working, only with the key on the door, holding it right or left goes up or down, if try with swich at door nothing, same with the rooftop, fck this car dude dammmm@@ianpgonzaga

[@D4rKiTo]

My car has been overheating, and even when I turn on the air conditioning, the fans don't spin at any speed. I turn off the car, then turn it back on, and the fans start working again. I've replaced the fuse box above the battery, temperature sensor, thermostat, the radiator thermo-switch, fuse box over battery and the relay box under the battery, but the same issue persists. Sometimes the fans work fine at both speeds, and other times they don't work at all. If I bridge the connector on the thermo-switch, both speeds work, at least when car is cold. (I can't try when car is overheating due temp goes crazy so fast). Any help? When car is cold is cold or its at +90 but not more than 30min fans are turning on at 96ºc and then temp goes back to 90-91.

[@ianpgonzaga]

Sounds like fan resistors starting to decay. Have you changed the fans themselves ??

[@D4rKiTo]

@@ianpgonzaga nope. Fans are my next option. I wasnt sure about them because everything works when I do tests in my house. Maybe fans are overheating 😝 and stop working after a while. Ill try to change them next week. Thanks mate!

[@D4rKiTo]

I'm updating here since you are the only who tried to help me💗💗 @@ianpgonzaga I think I've fixed it, and it had 2 issues: -An air bubble (I started the car cold with the expansion tank open and let the car warm up for half an hour). Result: There don't seem to be any signs of overheating anymore. -A faulty sensor (it was one of the cheapest). The other day, while monitoring temperatures while driving, I saw it change from 92°C to 120°C in less than 1 second and then drop back down to 92°C. Sometimes, going downhill, it would also drop to 70°C, which seemed like too much of a temperature drop to me. Today I installed a new HELLA brand sensor, and after driving for 2 hours, I haven't had any temperature problems. For now, it seems like I've solved all my issues. 👌👌👌👌👌👌👌👌

[@arry9534]

I pull out fuse 16 vent dosnt spinn...and if i conect plugs high speed works but low speed dosnt...

[@yuribarrientos1984]

Tk body!!

[@andre-77]

I tried pin 1 with pin 2 and the fans kicked at low speed without getting the ignition on….i tried 1 with 3 and the green fuse on the fuse box melted 😢 so I’ve a bad fans I suppose right?

[@ianpgonzaga]

Whoa! Hope nothing else got damaged - yeah sounds like replacement requirement.

[@andre-77]

@@ianpgonzaga yeah I’ll replace it! Thank you for your guide!

[@ianpgonzaga]

@@andre-77 you're welcome and hope you get to enjoy your TT soon.

[@stevefoley-v5v]

Ok I’ve been out and tested today only the fan near battery tray works, so I assume I’d have to change the fan that isn’t coming on?

[@stevefoley-v5v]

I pulled the fuse ignition on engine not running both fans didn’t run? Is that replace, so does that mean replace fan control module?

[@cobrapoduction26]

What if when I take the 10 fuse out the fans spin fast

[@ianpgonzaga]

Hi Noe. Yeah they should spin when you remove the rad. Fan fuse.

[@victorarinze6217]

Hello , thanks for the video , I have changed almost everything I could think of , FAN , CONTROL MODULE, THERMOSTAT, AND RADIATOR VALVE , yet the fan is not working and it not overheating. Please, what could be the issue here, please

[@ianpgonzaga]

@@victorarinze6217 hi. Interesting problem you have. If you're not overheating - I would check if your thermostat is functionIng correctly. I know you already said you changed it but is it the correct one, opening and closing properly and is it installed properly?

[@glynwalton9207]

Ive changed thermostat, sensor, coolant flush to no ovail lol

[@ianpgonzaga]

Oh no. Still overheating and no fans working ?? Maybe time to change the fans themselves.

[@glynwalton9207]

I'm going to hard wire it see if they work and if they do then im swapping control relay

[@ianpgonzaga]

@@glynwalton9207 yeah and if that doesn't work. Replace.

[@864ashx8]

So my fans do not come on at all when driving. They did not come on when I pulled the fuse, he lever they did when I bridged the wires. I replaced fcm, temperature switch, and thermostat. I don’t know what else to try. Maybe water pump?

[@ianpgonzaga]

Had you replaced the fans unit themselves? Sounds like the resistors are kaput.

[@stephenhancock2974]

Can anyone share details from their experience installing new fans on a 2001 Audi TT Quattro 225? Is it possible to work manipulate them out from the top or bottom without removing the nose? OR, Is it possible to remove the existing fans from the frame and install the new fans to the mounting frame without dropping the nose? (I desperately want to avoid disassembling the nose. Any solid experiences would be of interest and please include details where possible! Thanks

[@ianpgonzaga]

You can take it down from underneath. Just have to get the front of the car up super high for clearance.

[@Andrew-yy6gm]

Awesome video! My TT big fan stopped running while I was at idle out the front of my house, although after pulling out the #16 fuse, both fans ran. What could I do from here?

[@ianpgonzaga]

Get some thick gauge wire to do the tests in this video to begin ruling out what could be wrong.

[@thekop9049]

Not sure where is fcm on Mk5 gti 😢😢

[@ianpgonzaga]

I think it is part of the fans itself - not a separate box like in 8N generation TT.

[@thekop9049]

@@ianpgonzaga thank you so much 🙏🙏

[@stephenhancock2974]

Can anyone share details from their experience installing new fans on a 2001 Audi TT Quattro 225? Is it possible to work manipulate them out from the top or bottom without removing the nose? OR, Is it possible to remove the existing fans from the frame and install the new fans to the mounting frame without dropping the nose? (I desperately want to avoid disassembling the nose. Any solid experiences would be of interest and please include details where possible! Thanks

[@ianpgonzaga]

Hi. Sorry I thought I replied. Yes you can remove from.underneaty without having to remove the front but it's tricky and you need to jack the car up REALLY HIGH to do this.

[@zohairalimalick5931]

Have paid like 2k to audi dealership to know thermostat was faulty which after changing didnt solve the issue. Took it to another shop to be told its the fans that are faulty. Told me he tested the electricity to the fans. So I am guessing the control module is working fine its the fan itself. Tool out the fuse, didnt turn on any of the fans. When i turn on the AC it turns on the driver side fan (rhd) but the passenger side doesnt turn on. Absolutely stuck after paying a huge bills. Tested the old thermostat and it appeared to open up in boiling water. Just hoping putting a new rad fan will solve the issue.

[@ianpgonzaga]

Yeah I wonder if the dealer even tested things properly. Hope you get it fixed with the next repairs on the fans itself.

[@tindraxx7226]

My fans worked perfectly before but one day someone reversed into my tt, nothing bad happened he just cracked my bumper but 2 days later the fans stopped working. The previous owner changed the thermostat. Should I just buy the fans assembly? I bought the relay, when I disconnect my 16 fuse nothing happens.

[@ianpgonzaga]

Maybe check the plugs and wiring first at the FCM and at the radiator fans shroud first..something might be come loose ?

[@Tesadufh]

Hello, i have a cluster problem i guess, my temperature gauge going high then fan is turning on, there is no hot Motor, when i hit the temperature side of my cluster with my Finder :) it goes down . İ changed cluster temperature motors but still Same :(, i m trying to find solutions, do you have any idea for this issue 🙏

[@ianpgonzaga]

Hi Kemal. Sounds strange but it's like your cluster needs to be inspected for repairs.

[@martinnrhave6832]

I have a Seat Leon 1.8T where only one fan i spinning when i pull the #16 fuse. My guess is that the fan is broken. Does that sound right?

[@ianpgonzaga]

Yep. Replace fans. They should both spin up when you pull fuse 16.

[@antalkok]

So i pulled the fuse 16, both fans didn't on. Went driving, only 1 did work at low/high the other is dead i think?

[@ianpgonzaga]

Hey Antal. Sounds like it! Time for replacement or the resistor mod.

[@Barryd57]

Why not connect 12v directly to the fan using the high speed pins on the cable that attaches to the fan? Second, why not connect an 8 volt source to the two leads on the fan connector that provides low speed? By connecting directly to the fan, aren't we eliminating everything else?

[@ianpgonzaga]

I thought that's what I did but maybe not

[@amadozein]

Hey bro , May i ask what gonna happen if I deleted the thermostat specially im living in hot area most of the year

[@ianpgonzaga]

Your engine probably won't get up to proper operating temperature

[@ibiochateau3263]

Magnifico, que pena que no estan los subtitulos en Español, I have changed the thermostat, green sensor, radiator sensor, but sometimes the fans do not work, fuses are fine, mi TT I'm going crazy, thanks.

[@ianpgonzaga]

Maybe the fan control module (black rectangle box under battery tray) needs replacement ?

[@ibiochateau3263]

​​​​@@ianpgonzagaMagadang Umaga, Sometimes the fans come on, other times they don't, and when you stop the car the same, It could be the relay you mentioned (module control). Very kind, thank you. SALAMAT.

[@elielsandunguero]

What's the low resistor mod?

[@ianpgonzaga]

Hey there. It's where you add external resistors to the system in place of the ones mounted in the fan housing.

[@elielsandunguero]

I heard that they use mk5 fans but no idea how to do it .

[@ianpgonzaga]

@@elielsandunguero not sure they would work ... Or fit properly.

[@rossgrimson972]

Can't say I've ever made the thermostat blue, plenty of others though. Excellent explanation of the test process, thanks. Digging the Zen music vibe!

[@ianpgonzaga]

Thanks Ross. Had to go through all the motions to get to the bottom of everything (which was user error haha)

[@steambuns2283]

hey bro just asking are u filipino?

[@ianpgonzaga]

LOL. Yeah I am ☺️

[@outlander4ever241]

Hello Thanks for your video,it was very helpful. So i did the test for the fans and only the low speed is working. Do i have to change both fans or the fan the module can be the issue ? Thank you.

[@ianpgonzaga]

I would change the thermostat switch before going to change the fans which is less expensive.

[@outlander4ever241]

The one on the radiator ? Thank you very much.​@@ianpgonzaga

[@ianpgonzaga]

@@outlander4ever241 yeah that one just take sure it's the correct shape plug. www.google.com/search?q=audi+tt+8n+cooling+fan+thermo+switch&oq=audi+tt+8n+cooling+fan+thermo+switch&gs_lcrp=EgZjaHJvbWUyBggAEEUYOTIHCAEQIRigATIHCAIQIRigAdIBCDY4NDNqMGo0qAIOsAIB&client=ms-android-optus-au-revc&sourceid=chrome-mobile&ie=UTF-8#sbfbu=1&pi=audi%20tt%208n%20cooling%20fan%20thermo%20switch

[@arry9534]

hello, my TT overheats when the car stops, the temperature rises to 110 degrees, the fan starts and drops to 90 degrees, this is repeated over and over again, the fans do not rotate at slow speed, only at high speed when the engine overheats. when I disconnected the fuse 16, not one of them was spinning the same way when I turned on the AC fans, both are not spinning. I'll think about what to replace first.

[@ianpgonzaga]

@@arry9534 yeah good and also consider a fan control module replacement.

[@DufussMan]

Any advice for getting the actual plug off to the fan testing? Most of us don't have the bumper off and its real tight in there. I've been messing with mine for about an hour and it doesn't want to budge.

[@ianpgonzaga]

😲 with the bumper on and all trims in place it's going to be super hard to do this test. You'll need to teach down or move the battery out from its box.

[@DufussMan]

Thanks Ian. I just gave up. I think I'm going to order a Fan Control Module in the hopes that thats the quick fix. If i have to take the battery and tray out anyway I'm basically right at the FCM. Know any other way to test the fans?

[@ianpgonzaga]

@@DufussMan ahhh ok. This is probably the most well known way to test them. They can't be tested with VCDS like the newest cars because they're not part of the CANbus.

[@pakontomasz]

Hi can you tell me what should I do when my fans work all the time, I mean when I turn on ignition they are starting even though engine is cold.

[@ianpgonzaga]

Hi Pakon. Sounds like a busted fan control module.

[@markhamilton8198]

@@ianpgonzaga Which is supposed to be located under the battery tray. I'm in the US so I am not sure if things were done differently, but I just pulled my battery tray and all I have is car frame. Where is this module of which you speak located? My fans are always on as well, and I am changing the fans because they were worn out....and thought I should also fix this problem.

[@ianpgonzaga]

@@markhamilton8198 it's under the chassis rail (which is below battery trail) so it's like this Battery trail Chassis rail FCM

[@pjmccracken]

Great content and the best video I have seen on this yet, Thank you!

[@ianpgonzaga]

Thanks Peter! Really appreciate it!

[@wageemaislam4493]

Hi audi A3 over heat

[@ianpgonzaga]

Hi. Hope this video helps you to fix the problem 🙏

[@barbuandrei4316]

hi. does the 2.0 tfsi BWJ has that control Module? THX

[@ianpgonzaga]

Good question - no fan control module for the Mk2. There is a fuse box in the engine bay with relays - I would check in there for the fans relay - the rest is main ecu controlled. Your owner's manual should be able able to guide with what's in the engine bay fusebox.

[@barbuandrei4316]

@@ianpgonzaga thank you for the replay, i don t have the manual instruction, and someone told me that this problem is caused by the tuning soft. I have stage2+

[@ianpgonzaga]

@@barbuandrei4316 maybe try out factory tune (back up your stage 2) and see what happens.

[@barbuandrei4316]

@@ianpgonzaga that s what i will do, thank you. Is bizarre, i never heard that a tune can cause a problem like this

[@stevefoley-v5v]

I’m confused you said if pulling fuse 16 and both fans don’t run then you need to replace that fan, then you said after that if both fans don’t run, then you need to change fan control module?

[@ianpgonzaga]

Hey Steve - so this part? kzbin.info/www/bejne/kIeZqnSljLeBqZYsi=ft13OghbGFoTsrAE&t=63 I thought I was quite specific but maybe I spoke too quickly... Pull fuse 16 = if EITHER of the fan's DON'T run then you'll need to replace THAT fan. If BOTH fans DON'T run = replace FCM.

[@stevefoley-v5v]

Perfect now I understand, pulling fuse 16 my fans don’t run, bridging on thermal wires only one runs, the one near battery try, so this is still FCM issue I assume or fan issue?

[@ianpgonzaga]

@@stevefoley-v5v I would replace the fans first in this case E

[@stevefoley-v5v]

@@ianpgonzaga even though one fan works?

[@stevefoley-v5v]

@@ianpgonzaga you stated of both fans don’t run after pulling fuse 16, then replace FMC? Now you say replace the fans? Understand why I’m confused 😂

[@s916606]

Hey, how so if thermostat fail passing coolant down the fan wont start? My fan dont work at high temp, but remove fuse fan turns on. I wonder if is thermostat failing. I thought thermostat dosnt affect the fan at all?

[@ianpgonzaga]

Could be thermostat has failed closed. If the coolant UNDER the radiator temp sensor (triangle plug) not getting hot /circulating then the fan will not run. When it looks like the car is at temperature are the lower coolant hoses hot or cold ?

[@s916606]

@@ianpgonzaga thermostat has been replace 5 months ago. I feel the fan isn't turning on the low speed. I will try the pin method soon. I am suspecting the CFM is bad or the resistor is bad?

[@ianpgonzaga]

@@s916606 definitely do more testing to get to the bottom of the issue.

[@s916606]

@@ianpgonzaga thanks!

[@s916606]

HEy Ian, what tried the triangle pin method. fan works on both speed. I saw you changed the Fan control module. What does FCM do? will that be a good idea to replace? @@ianpgonzaga

[@albertsiciliano4209]

Very good video.

[@ianpgonzaga]

Thanks!! Hope it helps you.

[@walideamine9540]

Hello where can I get information about vcds how to use coding adaptation prof and thank you for everything

[@ianpgonzaga]

Hi Walide. What do you need to do coding for ? There is always the ross-tech information for reliable VCDS coding

[@walideamine9540]

Like hidden features abs coding when I change it thank you for your time ❤️

[@ianpgonzaga]

@@walideamine9540 there's not many things to change in the Mk1. In the Mk2 you can play with more things easily in the ABS With late model only. Early model is difficult to code.

[@walideamine9540]

Thank you so much ❤️ when subscription expired mk908pro autel you do coding programming or not

[@ianpgonzaga]

@@walideamine9540 sorry I don't know what you mean.

[@BigBootySeeker2]

Where did you get that wire? Thats the only thing stopping me from testing those fans

[@ianpgonzaga]

Just grab it from the wreckers or go to an electronics parts store to get wire that's thick enough.