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S3: Unit that controlls cooling fans and over run water pumps

Discussion in 'A3/S3 Forum (8L Chassis)' started by Plane, Jan 22, 2009.

  1. Plane
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    Plane Member

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    [Jan 22, 2009]
    Hi, I have a 02 S3

    The cooling fans are not coming on and when the car is turned off the electric water over run pump does not come on.

    These are both controlled by a unit that is under the battery somewhere.

    Can anyone tell me how hard is it to get at?

    Thank you,

    Paul
    #1
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  3. leshkin
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    leshkin Speeding in reverse gear VCDS Map User

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    [Jan 22, 2009]
    I had this on my old A3... Check the 30Amp fuse box on top of the battery as that was the cause of the problem for me.

    Not sure why Audi placed the fuse box there, but changing the fuse fixed the problem for me and I hope it does for you.
    #2
  4. Plane
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    Plane Member

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    [Jan 22, 2009]
    I checked that alright and it's fine. Will have a second look, would be nice alright but think I have to replace the unit.
    #3
  5. jimbobery
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    jimbobery S3

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    [Jan 23, 2009]
    I've noticed this on mine and suspected that the water over run motor wasn't coming on because of the cold weather?

    Should the water over run motor come on after every journey?

    Plane, if the unit you're talking about is under the battery I don't think it should be too hard to get at, battery removal is pretty easy.
    #4
  6. Plane
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    Plane Member

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    [Jan 23, 2009]
    Have a check to see if your fans are coming on. Is you aircon working at coldest?

    Getting the battery out is easy alright but the unit is burried a bit below the battery, think some hosing and other bits have to come out too. Not sure how far it's down but it's not directly under the battery.
    #5
  7. jimbobery
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    jimbobery S3

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    [Jan 23, 2009]
    Apparently the continued coolant pump should come on when turning on the ignition, so I'm going to unplug the lead to the pump and use a multimeter to see if it gets power, if it does it should need a new motor, if not its probably the control unit.

    I checked the fuse and notice in the handbook that the fuse is for 'continued coolant pump' and 'magnetic clutch', which must be for the air con pump? If so, I know my air con pump comes on because my aircon needs regassing, so when it does come on I can hear the familiar sound of an empty aircon system. Hopefully this means its simply the coolant pump that needs replacing?
    #6
  8. kevandalice
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    kevandalice Member

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    [Jan 23, 2009]
    What is this pump? Is it common on all a3 and s3 models?
    #7
  9. jimbobery
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    jimbobery S3

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    [Jan 23, 2009]
    Don't know if its on A3s but standard on S3s. It sits near the radiator and continues to pump the coolant round after then engine has been turned off so coolant will continue to flow round the turbo allowing it to cool.

    I'm even more confused now:
    - pump started after work when I put key in ignition.
    - Drove 8 miles home and turned engine off, pump wasn't running.
    - Few hours later, drove another 8 miles and turned engine off, pump WAS running.

    I'm hoping someone on here is going to say that the pump runs after a journey based on the temperature of the coolant/air/turbo, so sometimes it runs and sometimes it doesn't?
    #8
  10. S3BLX
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    S3BLX Member

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    [Feb 2, 2009]
    Where is this pump and how do i check if its working??????
    #9
  11. jimbobery
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    jimbobery S3

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    [Feb 2, 2009]
    Pump is to the top left, and behind the radiator as you face the engine bay. Aparently it should come on if you simply turn on your ignition (not engine). You can hear it whirring by putting your head near the left of the front grill.
    I'm checking mine after most journeys and it seems to be working. I took the plug connector of it to check for dirt etc (was fine) and since the it seems to run all the time, so maybe it wasn't on properly in the first place? Just going to keep an eye on it for now.
    #10
  12. mattyboy199
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    mattyboy199 Active Member

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    [Feb 2, 2009]
    I have the same problem, Jabba sport looked at mine with a multimeter & said its not the pump but an electrical fault. Usually in hot weather i will make sure the pump comes on by repeatingly turning the ignition on & off - that usually works.

    So it could be fuse or control unit related. Surely it cant be the fuse as it either works or it doesnt.

    Anybody know the cost & part number of the control unit ?

    matt
    #11
  13. Breezey
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    Breezey Member

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    [Sep 7, 2010]
    Hi guys having the same problem on my 2001 S3 AMK, only im getting a very quiet constant beep for about 30 seconds if i switch the ignition on and off it can only be heard with the bonnet open and sounds like its coming from the intake manifold but as the pump is right next to it id assume its coming from that, havent checked my fuses etc yet going out to do it now.

    Any help would be greatly appreciated.
    #12
  14. Breezey
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    Breezey Member

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    [Sep 7, 2010]
    Ok checked the fuze above the battery they are all fine, checked the connector for loose dirt thats fine, 1 cooling fan does come on when the aircon is on (left one if you stood at the front) no errors on vagcom that i can see so im out of ideas, oh the pump does have some purple gunk on it is that supposed to be there?


    [​IMG]


    [​IMG]
    #13
  15. S3PEG
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    S3PEG Member

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    [Sep 7, 2010]
    Main radiator fan - 6X0 959 455 F - £117.58
    Secondary Radiator Fan - 1C0 959 455 C - £109.38
    Control Unit - 1J0 919 506 E - £75.47

    These are dealer prices. I recently replaced all on my 1999 S3.
    #14
  16. Dazboss
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    Dazboss Like A Thristy Dingo ;)

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    [Sep 7, 2010]
    I phoned Bosch Tech today to find out some info on this part bloke wasn't helpful really.

    Just checked mine & the pump isn't in that place. But i know i have one. Where else can it be ?

    The purple stuff will be anti freeze leaking out. I know the fuse for it is in the main fuse board 10a FUSE NO: 16 as i checked mine the other day.

    Here is a screen dump from Tecdoc with some info which should help you all :)

    [​IMG]
    Last edited: Sep 7, 2010
    #15
  17. Dazboss
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    Dazboss Like A Thristy Dingo ;)

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    [Sep 7, 2010]
    Bosch Part Number 0 392 020 039.
    Listed as additional water pump.
    #16
  18. murran
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    murran Active Member

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    [Sep 7, 2010]
    both fans should come on together when either the aircon is switched on or the rad fan switches them in. pull the plugs off for the fans.... underneath job bottom right of the fan cowling. check the resistance of the motors the big wires. you'll find the one that isnt working has masses more resistance through it..... needs replacing.
    #17
  19. Breezey
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    Breezey Member

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    [Sep 7, 2010]
    Thanks for your help guys im going to do some further investigation tommorow looks like my main fan has gone then thats £100 quid plus maybe the pump atleast the control unit is working, will check the rest of the fuses aswell im doubting it thought its never the fuse when your short of money.
    #18
  20. Breezey
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    Breezey Member

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    [Sep 8, 2010]
    well ive cheked all the fuses should have done this yesterday but i was hoping 1 of them had gone but it hasnt all are fine so it looks like its a new water pump and main radiotor fan for me theres another £250 down the drain unless anyone ccan think of anything else it could be? havent check the fan connections yet didnt have time to get the covers off.


    Part numbers for future reference :

    After run water pump - 078 965 561 - £111.24
    Main radiator fan - 6X0 959 455 F - £117.58
    Secondary Radiator Fan - 1C0 959 455 C - £109.38
    Control Unit - 1J0 919 506 E - £75.47
    #19
  21. Breezey
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    Breezey Member

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    [Sep 11, 2010]
    Ok this is wierd ive just got back after a 20 mile journey and the friggin thing is working again !!!
    #20
  22. PBazBarrett
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    PBazBarrett New Member

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    [Jan 30, 2011]
    Hmmm was just wondering, mine seems to stay on an awful long time when ignition turned off keys out and car locked. you can still here it, after being stood a while I charged battery up, turned car over but didnt start and the pump continued to pump 4 ages, is this normal. after a good blast when I park her up the pump stays on for ages ? anyone elses stay on?
    #21
  23. morgan306
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    morgan306 Member

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    [Jan 30, 2011]
    Does this pump mean we don't need to sit in our cars with the engine running after a blast then? Sorry to jump in on your thread Breezey.
    #22
  24. Pabl0
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    Pabl0 Member

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    [Jan 31, 2011]
    Pretty much mate, but rather then sitting in your i find its best to take it easy and off boost for the last part of the journey, the the turbo will be cooler anyways and the secondary pump will be more effective thus not sitting in the car like a lemon.
    #23
  25. SIMPLESIMON
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    SIMPLESIMON New Member

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    [Jan 31, 2011]
    I had same problem with my after run pump not working AMK. Its **** on the brushes which stops the motor from working. Quick fix is to give it a swift beating with a stick, I use abit of broom handle. This knocks the **** off the brushes. Like you do with a sticking starter motor. Or you can remove and strip down and clean contacts. Its not easy to strip and rebuild as is a sealed unit, I thick theres a thread on vortex. Anyway try tapping the pump
    #24
  26. Breezey
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    Breezey Member

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    [Jan 31, 2011]

    Basicly yes, it circulates water around the engine and turbo after the ignition has been on/engine run, mine was playing up but now its working again think im goin to rebuild it, as for jumping in the thread its not one of mine but i would have said no worries anyway as its all relevant so good to keep it all together will help otheres in the future :)
    Last edited: Jan 31, 2011
    #25
  27. Agric04
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    Agric04 Member VCDS Map User

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    [Mar 24, 2011]
    I think my over run pump has just stopped working!

    I've only had the car a few months now and I thought I noticed it got louder than normal a couple of weeks ago, now it appears to have stopped working completely.

    I haven't checked anything yet, I know that my fans come on when I turn the a/c on but have yet to get the fans to come on through over heating, I guess we've not had any hot enough weather yet and I've not been sat stuck in any stationary traffic yet.

    Are these pumps a common failure part or is it more common to be an electrical problem? Need to do some investigating this weekend.

    Is there anything in Vagcom that would help me identify the problem, I'm assuming this probably won't trigger a fault code...or will it?

    There's always something to fix!!
    #26
  28. Breezey
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    Breezey Member

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    [Mar 25, 2011]
    Im 99% sure that vag com wont display anything, not all electrical items are covered as my main fan has died and doesnt show, there is a rebuild thread for the pump but youll have to be carefull as theres lots of bits to it.

    The pump should come on even if you only turn the ignition on and off briefly thats a quick test you can do but other than that its a new pump your gonna need and there £110 from the stealers :( and most scrapyards dont listen to what you want and think you want the engine water pump so its like banging your head against a brick wall.
    #27
  29. Agric04
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    Agric04 Member VCDS Map User

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    [Mar 25, 2011]
    Well looks like it is definately the pump that's at fault, sometimes it works, sometimes it doesn't.

    Thanks SIMPLSIMON for the tip of giving the pump a smack this seems to do the trick.....looks like I'll be saving up for a new pump.... £110 ouch...and it doesn't even make the car go faster!! boo
    #28
  30. s3dave
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    s3dave TFSI Hybrid

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    [Mar 26, 2011]
    Just took my afterun pump off and stripped it down, cleaned it (cant say i saw anything wrong with it to be honest) put it back still not working went for a run ........hey presto i hear it running when i turned the engine off...first time since i have had my car.....result!!
    What a nightmare getting it off the radiator housing....zero room
    #29
  31. DavidW
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    DavidW Member

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    [Mar 26, 2011]
    How much do you think it does? Obviously your car has been fine while it wasn't working.
    I took mine off a bit back because it was leaking quite bad and just joined the two pipes with a connector with the intention of fitting a new one at a later date (£100+ for a little pump!!). This thread has reminded me though so I've dug it out, stripped it down and sealed it back up (hopefully). It was leaking from the joint where the cap with the hose fittings screws to the main body. I'm hoping the silicone holds and I can remember which way round to plumb it back in!
    #30
  32. s3dave
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    s3dave TFSI Hybrid

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    [Mar 26, 2011]
    Not sure how effective but, its got to be better than nothing.
    it can only be plumed in one way round with the shape of the pipes
    #31

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