why are both my cooling fans on when i turn the car on?

[bagged00]

had a bad passenger side fan motor. so i replaced it and the driver side on too. now i turn the car on and both fans automaticaly come on. ive searched a little about it and what im reading is either the green coolant temp sensor, the thermostat, or water in the ecu. any way to dial it down to one specific problem?

[JolePatrol]

Usually coolant temp sensor will leave your temp gauge on your cluster to act weird (it will fall to cold randomly) the thermostat i'm not sure about, and the water in the ECU can cause the fans to run while the car is off draining your battery. A quick scan should tell you if your thermostat is stuck open/closed. My t-stat isn't throwing a CEL but it's stuck open when I scan it with my vagscanner

[bagged00]

thanks. well my gauge isnt acting weird, and my fans arent coming on when the cars off. and ive read a thread about a guy that was having the problem i was having and changed thermostat and said it fixed it. so i think ima start out with the thermostat. is the drivers fan always on and the pass fan comes on when the ac kicks on?

[Charles.waite]

thanks. well my gauge isnt acting weird, and my fans arent coming on when the cars off. and ive read a thread about a guy that was having the problem i was having and changed thermostat and said it fixed it. so i think ima start out with the thermostat. is the drivers fan always on and the pass fan comes on when the ac kicks on?

I would personally start with the relays under the ECU, check them for corrosion, clean/replace accordingly. Then I would move onto the cts (both the green and the grey one). A stuck open thermostat wouldnt cause the fans to kick on.

When cold, neither fan should be on. The passenger side one only turns on when the a/c is on, it has nothing to do with engine temp. The drivers side fan is correlated with engine temp.

If you turn Econ mode on the a/c fan should turn off. If they're both on all the time, you should really get your car scanned and report back with the codes. Otherwise our answers are just speculation and you'll probably just be throwing parts at the problem hoping one fixes it.

[JolePatrol]

I'd scan it before you throw a t-stat at it. I sure as hell wouldn't deal with that to find out that's the problem. As stated above, I'd check the relays under the ECU just to make sure since it can cause a lot of different problems. When I got water in my relays below ECU I was having the fan running when off issue as well as a random issue with my reverse lights turning on even when in drive.

[zz2h33]

could be as simple as clearing the DTC, i would try that first. if you have had an over temp situation and have a trouble code related to it stored in the ECU it will automatically turn the fans on all the time, even if you have fixed the problem. it'll do this until the DTC is cleared.

[bagged00]

I would personally start with the relays under the ECU, check them for corrosion, clean/replace accordingly. Then I would move onto the cts (both the green and the grey one). A stuck open thermostat wouldnt cause the fans to kick on.

When cold, neither fan should be on. The passenger side one only turns on when the a/c is on, it has nothing to do with engine temp. The drivers side fan is correlated with engine temp.

If you turn Econ mode on the a/c fan should turn off. If they're both on all the time, you should really get your car scanned and report back with the codes. Otherwise our answers are just speculation and you'll probably just be throwing parts at the problem hoping one fixes it.

can i scan it with just like a obd2 scanner or do i need vagcom? i dont have one, nor do i know anyone around me that has one. oh and also, since ive gotten the car i cant turn econ off. i press the button the light goes off and comes back on. i turn auto on, the econ light stays on. ive tried evertyhing to turn it off and it wont stay off.

I'd scan it before you throw a t-stat at it. I sure as hell wouldn't deal with that to find out that's the problem. As stated above, I'd check the relays under the ECU just to make sure since it can cause a lot of different problems. When I got water in my relays below ECU I was having the fan running when off issue as well as a random issue with my reverse lights turning on even when in drive.

i mean ill check the ecu but from the sound of it, water in the ecu compartment they come on when ever. mine dont come on when the cars off or stay on after i turn it off. the start right when i turn the car on. i found a thread where a guy replaced his coolant sensors and did nothing. he then changed his thermostat adn it fixed it. someone linked a thread to a guy that was having the same problem and changed his thermostat and it fixed that as well.

could be as simple as clearing the DTC, i would try that first. if you have had an over temp situation and have a trouble code related to it stored in the ECU it will automatically turn the fans on all the time, even if you have fixed the problem. it'll do this until the DTC is cleared.

what is dtc? ive never had an overtemp situation, but i did have a low coolant situation when my car was leaking antifreeze. when the pass fan wasnt working i had a CEL. now that the fan works(even though its always on) i no longer have a CEL.

hopefully i can fix it this weekend. i really dont want it running all the time and burning out the motor prematurely.

[Charles.waite]

If econ never turns off, you've got a problem with the A/C system then. Thats a pretty common issue, though fixes tend to be varied. Post in the regional sections asking if someone will help you with their VagCom in exchange for beer or something. I know there are some AZers in GA.

A/C issue could be the high pressure sensor/switch on the Condensor has failed. It could be a broken Compressor. It could just be your system has a leak and completely depressurized. Unfortunately, while you can fix AC youself, most people around here, even the gurus, will tell you to have a shop do it. Theres so much stuff that can go wrong. You'll need to get the system leak tested. If they find a leak, you'll need a new Dryer unit as well as once that gets exposed to air, its toast.

[BARRY]

i have 220k miles on my car and have very recently replaced both coolant sensors for old age assurance. my gauge cluster never acted weird, but my fans seem to kick on much sooner after engine start than in the past. then again maybe i'm just noticing it more recently than ever. in either case when i first start my car the fans may or may not be on depending on if it was really cold out or not. if my car was on previously my fans kick on when i restart my engine.

[bagged00]

If econ never turns off, you've got a problem with the A/C system then. Thats a pretty common issue, though fixes tend to be varied. Post in the regional sections asking if someone will help you with their VagCom in exchange for beer or something. I know there are some AZers in GA.

A/C issue could be the high pressure sensor/switch on the Condensor has failed. It could be a broken Compressor. It could just be your system has a leak and completely depressurized. Unfortunately, while you can fix AC youself, most people around here, even the gurus, will tell you to have a shop do it. Theres so much stuff that can go wrong. You'll need to get the system leak tested. If they find a leak, you'll need a new Dryer unit as well as once that gets exposed to air, its toast.

i just got the ac charged today from removing the condensor when i rebuilt my turbo. i used to work at a shop and brought it there where they use a machine to do all of it. he said it held a vacuum pretty well so he doesnt think it has a leak. for what reason i do not know, i have a ON/OFF toggle switch that supposedly goes to my compressor. dunno why its there or why you'd need it. maybe that may have something to do with it? i did notice today when i drove it about 15 min after charging the ac, the line has a little ice on them. ive seen moisture come from them lines but never them get like frosty looking? is there any relay i should look for specifically?

i have 220k miles on my car and have very recently replaced both coolant sensors for old age assurance. my gauge cluster never acted weird, but my fans seem to kick on much sooner after engine start than in the past. then again maybe i'm just noticing it more recently than ever. in either case when i first start my car the fans may or may not be on depending on if it was really cold out or not. if my car was on previously my fans kick on when i restart my engine.

lately here in ga its been VERY HOT think 105 today. but i stil dont believe both fans shoudl be on. hell i can barely get my temp up to half way on the gauge.

[Charles.waite]

If your engine never gets up to temp, then shit you more than likely need a new thermostat. Why didn't youmention that earlier?

Also that toggle switch is DEFINITELY not factory. Sounds like someone has been messing with your cooling systems. Take some pictures and post them up of all that stuff and I'm sure someone can help you out, electrical stuff is not my forte...

When you removed the condenser, was your A/C system exposed to the air? If it was you need to replace the dryer assembly. Even a few minutes of air exposure is enough to saturate a dryer rendering it useless.

Honestly, you've got to pull some codes, preferably with a Vag-Com otherwise we're shooting in the dark. You can also check the functionality of the thermostat with a Vag-Com to figure out if its faulty or not (sounds like it is).

[bagged00]

well damn, yea i had open ac lines for days lol. oops. i can try to get pics of the switch and wiring. i cant figure out where it taps in at. looks like i most definately need to find a vagcom. oh and the thermostat it gets up to temp, it just takes longer to do then before i did the repair. my guess is because that 2nd fan is always pulling air.

[Charles.waite]

If the fan is constantly on, on high no less, then it could be overcooling the engine I suppose. I would try to resolve the fan issue first though. Then see if the car still takes a while to warm up.

[bagged00]

oh its on high, you cant hear anything else around the car cause they're going balls to the wall lol. luckily i think i found a member with vagcom about 45min away from me.

[A4SoftWalker]

If the fans turn off after the car warms up then the problem is the upper coolant temp sensor.
Other than that seems u really have ur hands full there.

[zz2h33]

what is dtc? ive never had an overtemp situation, but i did have a low coolant situation when my car was leaking antifreeze. when the pass fan wasnt working i had a CEL. now that the fan works(even though its always on) i no longer have a CEL.

hopefully i can fix it this weekend. i really dont want it running all the time and burning out the motor prematurely.

DTC= Diagnostic Trouble Code. just because your CEL is not lit doesnt meant there is not a DTC stored in memory, and if it is coolant related I bet that is your problem. If you have a simple OBDII code reader clear the DTC and i bet your fan problem goes away. If you dont have one you can go to an autoparts store such as autozone and they can do this for free. if this doesnt work then i would go down the temp sensor route.

[bagged00]

If the fans turn off after the car warms up then the problem is the upper coolant temp sensor.
Other than that seems u really have ur hands full there.

fans dont turn off when the car warms up. but it doesnt really seem like its gonna be that hard of a fix. other people have had the problem and id be willing to bet its one of the 3 problems and all of them are inexpensive

DTC= Diagnostic Trouble Code. just because your CEL is not lit doesnt meant there is not a DTC stored in memory, and if it is coolant related I bet that is your problem. If you have a simple OBDII code reader clear the DTC and i bet your fan problem goes away. If you dont have one you can go to an autoparts store such as autozone and they can do this for free. if this doesnt work then i would go down the temp sensor route.

i got a budy with a obdII but ive never know them to be able to clear anything unless the CEL is on?

[bagged00]

this is why i say i dont think its the relay

if thermostat or any coolant temp sensor is faulty then fail safe triggers fan to be on all the time ( only with ignition on).

^^ correct,

the relay is the issue if the fans run while the ignition is off which i think is the case since the op said the battery is running dead.

this was off another thread i found.

[bagged00]

DTC= Diagnostic Trouble Code. just because your CEL is not lit doesnt meant there is not a DTC stored in memory, and if it is coolant related I bet that is your problem. If you have a simple OBDII code reader clear the DTC and i bet your fan problem goes away. If you dont have one you can go to an autoparts store such as autozone and they can do this for free. if this doesnt work then i would go down the temp sensor route.

well the p2181 CEL i had before i replaced my pass fan motor was hanging around in the background as a DTC. however after deleting the code, both of my fans are still runing:(. tomrow im going to check out the relays, probably replace the green sensor for the hell of it since i can get it for like 5 bucks and then if not that ill look into the thermostat. my gauge has a problem geting up to half way seems to want to fluctuate in between 1/4 and 1/2. so the more i think about it, the more i think it may be a thermostat.

[diagnosticator]

If the fans run as soon as you turn the key on, with a cold engine, there is most likely water in the ECU box. This has nothing to do with the t-stat.

[bagged00]

it may be i dunno. i hope it is something that is that easy. just saying off most the research ive done about it, everyone that had a problem with relays said their fans were running while the car was off. i havent seen one where someone said the fans always run when the car is on but never when it was off and it be the relay. not trying to be a know it all just the information ive gathered.

[bagged00]

ok little update. so i changed my oil and green coolant sensor today. still nothing. checked my relay and to me they seem like theyd be good, no water it doesnt look like

anywya to test a relay?

also here is wher the wire was tapped into my compressor. the cut the plugh apart then tapped a wire into where they spliced back together i have no idea why?part of me is afraid to wire it back normal cause im not sure if the clutch is always staying on or what?


also broke a hose today. need to know where to get it


see where the hose goes down? what that connects to is what broke


i think its number 10 where it broke off at. not number 10 it self, but the stud that number 10 slides on too. it was a round hose slideing onto a square stud. any idea on where id get something like that?

[Charles.waite]

I would head over to 034's website and pickup a full silicon pcv replacement kit. There's a good DIY on here to replace it. The hose that broke (same thing happened to me last year) is a piece of shit plastic hose that WILL break again in a few years time. The silicon kit from 034 should last as long as you own your car. It's a really high quality kit.

[bagged00]

before turbo repair, id spike 21psi and drop down to about 18psi. before this hose broke, i was 15psi at almost full throttle, and now i runn full throttle after the hose broke im runnig 14psi full throttle, so i dont know what to do. check vacuum hoses? and fixes that see if there is a leak? btw any recommendations for cooling fan? i duno if to do relay or thermostat?

charles i dont have a clue what the hose looks like or how it really runs? seems like you have to take the intake off to get to it? can you help me with picking which one i need?
http://www.034motorsport.com/engine-...t-c-28_61.html

i dont think i need those hose that i took the pic of. i need the one that hooks to it. looks like it goes under the intake manifold?

[bagged00]

any recommendation on my cooling fan fix guys?

[bagged00]

so my new hoses will be here tomorow from 034. so here's my question. im thinking im gonna be changing my thermostat. i let my car run for about 15 min and pulled the cap off my overflow tank without any pressure didnt over flow or anything. my car fluctuates from 1/2 to 1/4 mark on the gauge. and i know yall say that they have nothiing to do with the fans, but we will see. ill be running vagcom tomorrow on it but not realy sure what ill be looking for to find defective sensor or thermostat? anyways so my question. when i put those new hoses on under the intake, im going to pull the intake. so could i kill 2 birds with one stone and knock out the thermostat while the intake is off? or will i still have to pull the alternator and all that?

[nogovitsin]

Hey bagged00 , i got 2006 a4 2.0 T FSI and have the same frkn problem. In the beginning , after diagnostic in dealership , they sad a bad stat. So i replaced the stat , the engine check light went off and i have not any DTC's .But my both fans running at full blast after couple of second after you start the car. My next step was the CTS , replaced that. But the problem still there. When i turn my ECON off , the condenser fan still running.Check all the electrical connections and now i am just lost!!!! Need help on my next step,thks!!!

[1900gte]

I had the same thing. 2003 1.8T BFB
The problem was the coolant temp sensor.

16500 - Engine Coolant Temp. Sensor (G62): Implausible Signal
P0116 - 008 - Implausible Signal

When starting the car cold in the morning the fans run wild.
The dashboard reading was fine.

My car is already on its forth temp. sensor.

[Jazzman848]

Hi I am new to the forum, but I am having somewhat similar issues. My 2005 audi B6 1.8t had an issue with the thermostat stuck open, which I personally replaced and at the time I also did a coolant flush. I used Peak 50/50 the pink stuff which is applicable to the vehicles cooling application. I also replaced the two coolant temp sensors, now the car would from a cold start kick on the two engine fans at high speed. The fans would run for about 10 minutes then shut off. The car also experiences slow warm up time and would not reach the optimum engine temp, like a stuck thermostat. I have checked all the connections and the ECM for water which is a common issue but I have seen none. There are no coolant leaks but the trick here is that the car produces heat for the cabin even when the needle barely registers temp. I did look up some codes that was given from the OBD:

Codes issued at the time:
-P1292 No signal to thermostat
-P0411 EVAP Emission control system Incorrect Flow
-P1602 Voltage too low (Battery??)
-P3081 Engine temp too low

[ekasanya]

ok little update. so i changed my oil and green coolant sensor today. still nothing. checked my relay and to me they seem like theyd be good, no water it doesnt look like

anywya to test a relay?

also here is wher the wire was tapped into my compressor. the cut the plugh apart then tapped a wire into where they spliced back together i have no idea why?part of me is afraid to wire it back normal cause im not sure if the clutch is always staying on or what?


also broke a hose today. need to know where to get it


see where the hose goes down? what that connects to is what broke


i think its number 10 where it broke off at. not number 10 it self, but the stud that number 10 slides on too. it was a round hose slideing onto a square stud. any idea on where id get something like that?

Where is the location of green coolant temp sensor?

[lyleswk]

Look about half way down the link below:

http://www.a4mods.com/index.php?page...tml&category=5