2002 VW GTI Cooling Fan Test (Part 1)

Watch Part 2 here • 2002 VW GTI Cooling Fa...
One thing missed in this video is water pump flow. This can be checked by looking at the smaller coolant hose entering the expansion bottle. There should be flow coming from this hose with the engine hot (possibly cold too). (Thanks to all who corrected me on this variable and sorry I missed this in the video)
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Here is the link to the combustion leak tester
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On ScannerDanner Premium I will bring you right into my classroom at Rosedale Technical College. You will find page for page lectures taken right from my book as well as exclusive classroom type case studies. What is so special about these classroom case studies? I pull live problem vehicles directly into my classroom and we troubleshoot them in real time, using and applying the theory and testing procedures we learn during the classroom lectures. There is no better on-line training of how to troubleshoot automotive electrical and electronics systems anywhere!
Disclaimer:
Due to factors beyond the control of ScannerDanner LLC, it cannot guarantee against unauthorized modifications of this information, or improper use of this information. ScannerDanner LLC assumes no liability for property damage or injury incurred as a result of any of the information contained in this video. ScannerDanner LLC recommends safe practices when working with power tools, automotive lifts, lifting tools, jack stands, electrical equipment, blunt instruments, chemicals, lubricants, or any other tools or equipment seen or implied in this video. Due to factors beyond the control of ScannerDanner LLC, no information contained in this video shall create any express or implied warranty or guarantee of any particular result. Any injury, damage or loss that may result from improper use of these tools, equipment, or the information contained in this video is the sole responsibility of the user and not ScannerDanner LLC.

[@hynekdlouhy8121]

I clicked on the video because of the fan problem, i watched it because of you being so nice to your son, to get him know about everything, it so nice

[@DJDevon3]

You make it look so easy. Beau has one hell of a dad. You're both awesome. Great job.

[@liftingafterdark3241]

The best explanation of the vw fan circuit!! Thank you!!!

[@kirkyoung6962]

Great video very straight to the point troubleshooting diagnosis.

[@GermMartinez]

This was such a great video man! Love how you showed your son step by step and mostly me as a viewer. Some people don't even do that. I appreciate this video so much! Great job and thank you!

[@ScannerDanner]

Thank you so much!

[@lhaynes8024]

So good to see your son working with dad ...your so good with him passing on your knowledge and he asks some great questions aswell great video helped me out a lot👍👍👍👍

[@SteveRobReviews]

Well done- this is thumbs up for Mr. Beau Danner - hope to see you again helping your dad and asking lots of questions so you can learn just like we all do. Great Job Beau

[@EXOVCDS]

Broken water pump impeller... check for coolant flow back into the reservoir. No flow, needs a water pump.

[@ScannerDanner]

great tip Thomas, I missed the coolant flow to the reservoir comment. I will have Pete check that right now. Also sorry I missed that variable in the video.

[@EXOVCDS]

ScannerDanner We can't think of everything all of the time... I'm excited to maybe having been of help!

[@ScannerDanner]

***** absolutely! thanks again

[@SteveRobReviews]

Pretty sharp Thomas- you are the guru when it comes to VW. Fantastic channel as well, I have learnt soooooo much .

[@EXOVCDS]

Steve Rob Thanks for the plug!

[@Newby682]

very helpful information here, intelligently explained also. thankyou and you are setting a great example for your kid

[@ScannerDanner]

+B New thanks so much!

[@alarjmammal5154]

What a pleasure to watch your razor-sharp troubleshooting, Mr. Danner. Thanks to your very logical process, as well as reference to the schematic in your video, it's now obvious why our '03 Jetta 1.8t's, no-fans-at-all problem was such a poser... not only the Fan Control Module failed, but the Coolant Temp Sensor as well. That's what threw me - Pulling up the fans red/white, low-speed circuit got them both spinning, but no hi-speed fan operation... Sure - Both were bad! Again, thanks a million. BTW, what is that killer laptop application you use in the video? Man, would that ever be nice to have.

[@jimkillen1065]

Great test and teaching your son . I just mentioned your advice on testing a fuse on my ac and fan on my tdi jetta . I changed out the module I had a spare and no clue how this system lol and that did not fix it . It was a fuse on top of battery that would light up a test light but it had the crusty on the blades of fuse . Cleaned the blades and sure enough the fans worked ac came on . So after that I thought well Paul said under a load while I drank a cold beer . Lesson learned thanks for all you do

[@meloramccoy1968]

Using the wrong coolant! Greens bad pinks good

[@ScannerDanner]

+Melora Mccoy bad design too

[@damianbooth8019]

Great vid mate. Very well explained and has helped isolate the problem I am having. 👍👍

[@SimplyDiagnostics]

Bo is awesome, I wish my son would come to work with me. On a side note, it’s amazing how many stab marks and broken connectors we come across as Diag techs, it’s scary.

[@nicovink7745]

I had both fans not running. Step 1 is to pull fuse 16 from the fusebox by the driver door. Contact on and both fans are running, so fan motors are both good. Step 2 is to check the airco system. If it's pressure is too low, both fans will not run. You can look this up in VCDS 08 Airco/Heating > Advanced Measurements (or something like that) > select Compressor from the selectboxes. If it has the value 3, it means the fans are not running because sensor F129 provides information that the airco system pressure is too low. This will result in the A/C clutch not engaging, and both fans not running. My car just needed a airco service.

[@fandf1449]

when I check the fan by rewiring on the connector from the temperature sensors, the fans work for 2.3 seconds and stop working, what could be the problem Thanks in advance

[@losesparkplug1190]

Nice cool helpful video, I have a 1.8T I think GLI 2002 Jetta 5 speed.

[@Flowtester1]

He said awesome when the fan came on when he touched that connection. He will remember that forever. That’s so good to get your young kids out to do this stuff. He might become an electrical engineer now.

[@tsriftsal3581]

It's getting dusty in here. A problem solver is born. Thank you for sharing.

[@guitarman4u44]

Thats how they run up your bill. Flushing it didn’t need and all the other stuff it didn’t need. Just put the switch on it and your done. There just ripping people off in these shops. Ive fixed these for $14 relay switch.

[@frecmenta5114]

I connected to the battery the red thick one on negative and the other two on plus at a time. The white/red thick one made the small fan turn. The thin yellow/red one did not spin nothing. I have a big fan problem but now the small fan won't spin...may be cos its 5 celsius outside..or I fried the relay or what?

[@ashleyderbyshire5023]

nothing happens when i bridge either of the connectors on the thermal switch connector, does that mean i have a power supply issue to the thermal switch?

[@kmank08]

Hey, what is wrong if I get low speed working normally, but when I try the red/ yellow high speed, I get nothing? Still a bad thermal switch?

[@mototechno834]

Hi Paul...I want to know that what activates this coolant fan thermal switch??? Is it the temperature of the radiator or does the coolant temperatur sensor activates it??? Thank you.

[@MarioReyes-iy6xg]

Great job I learn something today thank you and your helper.

[@o1r2l3a4n5d6o7]

Thank you so much for this video. I was able to test and diagnose why the fans were not working on my '04 Jetta 1.8t. I found no power getting to the thermo switch and found the contacts on fuse 8 were melting and corroded. Cleaned the contacts and works great. Thank you again.

[@randyvannorman560]

Hey, thanks for the info in the video.....tested found (facing car Right fan) not coming on... Do you have site where I can find the acceptable ranges for Reading from OBDII like (Oxygen Sensor)..etc Thanks....

[@ScannerDanner]

It is becoming more and more difficult to answer questions here. I have 80,000 people asking me for help now. So I have created a forum to help you guys better. It is free to join and we can exchange pictures, wiring diagrams and waveforms if needed to help guide you through the process of troubleshooting your vehicle. Thank you so much! Hope to see you there. Paul Danner (ScannerDanner) www.scannerdanner.com/forum/post-your-repair-questions-here.html

[@therealspixycat]

This is a simple high amperage switch that switches the 12 volts to the fan directly. If it was ecu than it would be a thin wire

[@toyotatechMDT]

Nice work again Beau! I assume your splitting your fee with him Mr D? You could check for water pump operation on any VW due to impellers falling off. You want to see flow into the expansion tank from the small pipe. Great video, thanks as always.

[@ScannerDanner]

great tip! I will call Pete and have him check that right now. So to be clear, there should be flow on that smaller hose all the time regardless of t-stat opening or closing?

[@FlameDudeUmai]

Thanks Paul i am going to work tomorrow on a volkwagon beetle 2.0 2002 and the cooling fans donot turn on.. Some time they do.. I run across your video. Thanks it will help me alot with the diagnostic.. Thanks from Franco Perez.. God bless you..

[@ScannerDanner]

Make sure you watch part 2!

[@nando4755]

Good afternon my man !! How were your leads conected when you did the test it does not show that on the video ? The one u put on power was that conected to battery positive and the other one to ground ?

[@imamaestro2476]

Brooo omg YOU HAVE THE DIAGRAM for me! I have been struggling with both fans running on fast speed the second you thrn ignition and after turning ignition off they will run for like 10 more min. These will help me so much narrowing down my options!😁

[@ScannerDanner]

For future needs. You can pay $20 for all of the service info for your car. However Mitchell is weak on Euro. eautorepair.adtrk.biz/?a=10817&c=24&p=r&s1= The diagrams are the same as what I'm showing you. The service info (description, operation etc) is typically weak on Euro stuff.

[@dondangerous4553]

Paul, good to see you have such a smart apprentice for his age! Great circuit testing and I haven't watched the part two yet, but I suspect like others that you may have a loose/broken plastic impeller. Common on these and easy to miss, specially when it's had all that work. Best wishes from Vancouver, and wave HI to May for me.

[@joshuab.fletcher5245]

So if i jumper it and get low speed but no High speed……….what part is bad???

[@ReedsAuto]

You can also rent that kit to check for combustion gasses in the cooling system from AutoZone.

[@michaelanolfo4727]

I love how you are teaching your son with patience.

[@adityasatya4630]

Sir thank u for the video .. Its very informative... I had problem .. With high speed fan... I do the same things with u Jump the wire at thermoswitch.. Low speed are good But at high speed doesnt work... Can u explain what should i do next... Is it control module problem ... Thanks for support .. Andsorry for my bad in english... Greetings from jakarta .. Indonesia

[@ScannerDanner]

Did you watch part 2?

[@kainnonbooker1422]

So, my 2000 Audi TT Quattro has no fans. And I’ve pinpoint no low fan being cause by a faulty fan switch. I’ve delidded a control module an have found, even with ac, I have no high fans. The high relay closes with the ac clutch relay in the module, and even doing it manually without ac, no high fans. Where should I check as to why I have no high fans? (Currently still have the faulty fan switch installed).

[@kainnonbooker1422]

Just check continuity at the fans, I have continuity on low circuit but none on high. Both fans have a red-black wire (low fan power), a red-white wire (high fan power), and brown-Black wire (ground). Correct me if I’m wrong. But, red-black to black-brown read continuity while red-white to brown-Black read open. (This is true for both fans). I also power probed the relay connector. Bright light when testing the power side to ground on battery, dim when testing the ground side (or the side that feeds power to fan) to power from the battery. Ohms from module connection to fan connectors reads .2-.3ohms on both fan connectors and for both high and low circuits. Am I too assume that the high side in my fans are my problem for no high fans? I just don’t understand how I have 12volts across the control’s connectors with everything buttoned up, but basically looks like OL when isolating the fans. Possible short to ground would do that, but then the fuse 16(?) atop the battery would pop cause nothing else gets powered to act as a load. And I can’t see myself missing/improper contact with my meter on both fans but still having proper contact on low speed on both fans. I even tested three times to make sure. (Unless I was wrong about the wiring as stated above.)

[@ChristopherPuff]

Great video. I was struggling to figure my fan issue again in my wife's New beetle and this video is the solve. Thanks again. Great to see you involving the young man in the video,

[@maladasus]

hi , plz help me i have in pin 1 négative pin 2 positive pin 3 positive it's normal ?

[@flashdkr]

quick question I have an 02 jetta vr6 . my fans stopped working on me. I have checked for power on the red wire but when I jump it to check the high and low speeds nothing happens what else can it be ?

[@flashdkr]

+TrainedHotdog No ended up junky the car

[@mcneur0]

What tools do you use in this to put power to the fans and test if they work? I’m needing to do some fan troubleshooting on my 2004 Audi. Can’t find the right electrical testing probes anywhere!

[@ScannerDanner]

I don't remember using any special tools in this video? Just my test light, but I do have tool pages that you can look at that show most of my equipment. www.aeswave.com/scannerdanner-c512/ www.amazon.com/shop/scannerdanner

[@lavirecord6467]

I do exacly what u just did. I find out that when I test the red/power to the red/yellow the fan don't run. what now?

[@vw602pr]

pin 1 and pin 2 make low fan run, but on my car pin 2 and pin 3 will not make the high-speed run, I change the fuse box by the battery and the module, any idea??? thanks

[@ScannerDanner]

not without looking at a wiring diagram of your system eautorepair.adtrk.biz/?a=10817&c=24&p=r&s1=

[@puonjairo777]

What would I do if one fan don't work? In my case the high speed.

[@TR1P_L3G3ND2]

J. R. Puón did you ever figure out what this problem was?

[@iiLoveeAnahii]

Very good video help me to do same in my daughter's beetle thank you very much I SUSCRIBE to your CHANNEL I recommend it

[@eddiemunoz6002]

One question. My fans didn’t turn on high when I did the computer one. Do I have. Anda computer or??

[@ScannerDanner]

Without looking at a diagram and knowing exactly what you did and how you did it, I cannot answer. Post this to my forum www.scannerdanner.com, it is free to join and we can absolutely help you there.

[@JoelAutomotiveInaction]

nice video Paul I did not see the link for the head gasket, what is the name of the tool (software) you were using to draw on the diagram at the beginning?? thank you

[@kenyamyhomee]

What would you have done if you didn't have the wiring diagram? Just thinking out loud here. Would it be harder to sort out?

[@ScannerDanner]

Absolutely! I wouldn't even attempt to troubleshoot an unfamiliar system without a diagram

[@droopy761]

Where did you get the wiring diagram? (what 's the name of the package)looks to be clear and easy to read. thankyou

[@ScannerDanner]

droopy761 www.scannerdanner.com/forum#/20150619/where-to-get-wiring-diagrams-4839109/

[@AJ-gv8rx]

Dude, thank you so much, that was very informative!

[@ScannerDanner]

No problem!

[@jossan9827]

Excelente video. Greetings your son.

[@kenburke0351]

Most informative video ive ever seen. Your son is lucky to have a dad like you. He will be a great mechanic one day if that's what he chooses to be.

[@jarodlloyd6429]

What is the wiring diagram you used cause I need to figure out why my fan ain’t turning on.

[@ScannerDanner]

Here you go eautorepair.adtrk.biz/?a=10817&c=24&p=r&s1= Same diagrams I use

[@erickrojas3560]

My high fan speed wont engage with this test

[@syednurnaim4800]

Good education 🇩🇪🇲🇾

[@abqadeer8168]

Hey mate, You know whats the operational current for these fans?

[@ScannerDanner]

Not sure my friend, sorry

[@karowinn8862]

what if only one speed on the fan works

[@smilingcopycat]

High five too Bo from Sweden!!!

[@littleblazer355]

Great info. Thank you both

[@vtxjay1300]

Man, this is an awesome video. Spent hours on fourms reading with no luck. Your video helped me tremendously! Thank you !!!

[@everardocamacho5063]

Great video mr Danner, big five to your helper,just one question,can I use a power probe? For this bypass test,thank you again and cheers from ontario ca,

[@RAFICKDAMISONMOYO]

Great Video. Fantastic

[@Discretesignals]

Was thinking about the block test kit and I have run into vehicles where it wasn't accurate. Thinking about building a combustion gas detector using the guts from a cheap carbon monoxide detector that you can buy at any hardware store. Maybe stick in in a PCV pipe that is vented at the top.

[@user-cm9uh6sj7n]

useful content

[@laszlototh5956]

Wooow!!! There is the name of my country written on the coolant hose at 7:25 . This is the 1,8T engine made in Győr, Hungary!

[@LynxStarAuto]

I'm late to the party, but yes broken impeller definitely. I'm also not a big fan of the aftermarket metal impeller pumps either. Btw, I didn't like the way the fans sounded either. One of them sounds like it is creaking, which I have seen happens because the magnet will actually spin in the housing.

[@airkewld0scar]

What's the easiest was to remove the switch? I've been trying from under the car and no luck. Thanks in advance.

[@Buciasda33]

I had the same problem, you have to get under the car and lift the little plastic clamp with a screwdriver in order to pull that triangular plug out. In my case it was the big fan motor, I disconnected it's plug and put an Ohm Meter across it, but it was an open circuit on both speeds / coils. After that I took the fan out, it was held with 3 Torx T30 screws and disassembled the back of the motor, it was a two man job, someone has to hold the fan so you won't brake the plastic fan and someone has to use a screwdriver and a hammer to pry apart the back of the motor (where the wires come out) I have finally discovered that the charcoal on one side got stuck, it wasn't sliding properly. I blew some air and moved it with my hand a little bit until it went smoothly. I assembled the motor and checked it's resistance again and it was about 1 Ohm, put it on a 12V power supply and it worked on both speeds

[@maveric0738]

By jumping, and both high and low speed fans are working correctly, you would need to replace the fan switch? If the fans do not come on, Fans need to be replaced?

[@victorbeltran3075]

It's cool, but I do not know if you will answer questions I have a 1998 dodge grand caravan the fan weren't working, because the radiator fan control I when and change that, but now if my temperature swish is plug the fans don't work, but If I unplug the temperature swish the fans will work just fine but if I plug back the temperature swish back on the fans go off please if any body can advise me in which direction to go I'll appreciate a lot thanks for been this helpful JAHOVA GOT will bless all ways again thanks a lot

[@ytnapreppord9862]

Hey man I just bought a 2003 Volkswagen Golf and I’m trying to figure it out how to put my relay on my fan because the guy who I bought the car too is he just by past it without the relay which is the switch(manual switch) keeps on burning and I just bought a switch again

[@benrich6376]

Ha. I've just done a 2002 AUDI TT 1.8 (almost identical wiring) with this exact problem, using this exact method. Apparently the modules go a lot, but this too was the thermoswitch. :)

[@hhawki3]

I tested the red/white to the red/yellow and the high speed fan wouldn't run. I tested the power/red to low speed and power/red to high speed and they both worked.

[@bornlucky2]

hi dan when i bridge a connector block i like to connect the jumper wire to the load connector first and the supply connector last to reduce the chance of a short circuit (blown fuse) by the loose end of the jumper wire. great video thanks again.

[@tbz02]

I hope my nefew gets involed with me doing auto repair and diagnostics. Ps. So it won't break the car. Lol !!!

[@tbz02]

I hope my nefew gets involved with me doing auto repair and diagnostics. Ps. So it won't break the car. Lol!!!

[@slowjoe56]

Anybody have a clue as to how to identify a factory water pump for a 01 1.9 vw water pump?? Oh and good video!!

[@jarinwilson9539]

I have to get this off my chest. On off road utility vehicles(we don't just work on automobiles) I have actually removed the radiator fan temp switch and used a small butane torch to heat it up and see if it functions(closes, continuity on a ohmmeter) Sort of a crude method but hey, I often have to improvise.

[@lonrolvos6088]

when I say overheat. I should clarify, the needle dances over the middle line where it usually holds. it only does that in traffic or red light. But it also happens right away drive a mile and it's dancing. dosent go to far to the right.

[@lonrolvos6088]

dude, you say it took you a while to get the connector off ... I past a while hours ago. I am about to hit it with an axe. Not everyone knows as much as you. How Do You get It Off?

[@jarinwilson9539]

I'm damn proud of you guys in the comment section. That is absolutely correct, if the radiator is NOT getting hot enough(lack of sufficient coolant flow) that fan will never kick on to begin with. These German vehicles are notorious for impeller issues. Awesome job guys!

[@GrumpyTy34er]

Any advice for taking that connector off of the plug? My 2002 Golf has been having a problem with the fans running whenever the key is in the ignition so I feel like this could be part of the problem.

[@kaashifawan3649]

Hey great video!! Kids lucky to have Learnings at a young age.. So my issue I have that the low speed comes on but when I put my power to high speed nothing happens, fan don't move, what do you reckon it could be? Sounds like a silly question thanks

[@sinegra30]

Thank you!

[@guayaco-dm3vu]

I was wondering when I was going to see you comment Thomas...Sure only when it comes to the vw stuff hahaha.. Very good video Paul...,show us more euro stuff pretty please..lol

[@ChicoDeon]

You are the MAN SCANNER DANNER.ThankYou for all Your hard work.I have upped my game a lot just from watching Your videos.

[@Sublimewales80]

hey . i have asked on a few forums but havent had much luck . my fans dont come on even with air con turned on . My understanding is they should come on slow speed , i havent had overheating yet. I have had a new temp sensor fitted along with a new thermostat . i have tried the jumping like you showed . and fans kick in so would this suggest the switch ? thanks

[@mikebrennan4534]

Thought i had you for a minute. Then at the end you made the comment about the t-stat. Recently had a Honda civic with same issue. Another shop tried fan temp switch and fan. Found bad t-stat. Fan switch was on cold side of t-stat even though temp gauge sensor was on hot side. Never understood why any manufacturer wouldn't put controls on engine side.

[@jarinwilson9539]

Sometimes I will intentionally ground the coolant sending unit, depending on the design just to re-create an overheat condition(verify if PCM responds by operating cooling fans in fail safe mode) It is imperative that the PCM sees the condition as well so 'tricking' it sometimes is also beneficial. Just be cautious that you don't cause engine damage from excessive heat.

[@nando4755]

I men the bypass test

[@timothypoblete8376]

Great videos I wish I my dad got to teach me some car skills, awesome..! I have a 2003 gti and I can't get the drivers side fan to work to get my a/c started. I installed new fans, FCM and pressure switch. Fuse and connections are getting power. Passenger fan works with a/c and when temp goes up to cool car. My friend and I think it is the cooling fan switch on the radiator. You mentioned in the video it was kinda a hassle to remove do you have any pointers. And any other suggestion on why more a/c fan is not kicking on? Thanks you for your time and help. Can't wait to see more videos..!

[@chass5438]

1:21: It is for me !

[@Aventuras_en_Moto_Hn]

Awesome video, easy to learn, i have one question, the thermo fan swicth have 3 +wires where is located the ground??? Because i really need to clean that bolt ground thanksss a lot, grettings from Honduras,,

[@gotwebsite1]

Thnaks for making this video.. Helped figure out the fan on my Audi TT is not working

[@tuliog4178]

Thank you very much for this video, I hope it helps me find my mk4 jetta fans problem. Cheers. (I like your assistant, he's a smart kid)

[@lonrolvos6088]

I used a paper clip to jump it and nothing happened. So switch is shot? No fans no nothing. spark in one pin.

[@calito96]

great video, what if my high fan is not working? did the same excat trouble sgooting as you did. where should i go after tht...

[@prashantshelke4386]

Hi sir m having issue with my fan , actually its start immediately while i swith on key, and showing error code p1672 in scanner, and showing error Circuit / Short To Gro

[@dreamer2355]

Paul, that hyper link for the combustion tester isn't working. Or it's my iPad lol. Great field work as usual!

[@michaelhamilton8107]

I can see there is Green coolant in the expansion tank, VW need a specific type, that’s what the G12 means on the graphic on the side. G12 is pretty bright pink. I bet there’s been too much corrosion going on all through that motor and that’s what the root issue is.

[@guesswhomartin9249]

This is so awesome. Teaching your son at a very young age. I have a lot of respect for you guy, Keep up the good work.