Fans not switching on

Discussion in 'General Technical Discussion' started by noony, Oct 31, 2012.

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  1. noony

    noony Hesitantly Boosting

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    On my way to work yesterday I noticed my temps were up quite high, so i quickly pulled into a servo to suss things out.

    Water was boiling in the overflow etc...I let it cool down, finally pulled off the radiator cap and it was pretty much disintegrated...lol
    After fishing the spring etc OUT of the radiator, replacing it with a new one and filling the radiator back up with coolant and water I thought my problems were over!

    Not so much...Seems the fans are not turning on and my temps are going up over half way.
    I only replaced the radiator 6 months ago after the common crack appeared in the top tank.

    Ive read a few posts on here now and am going to run through the things i need to check.

    Just to be clear, NONE of the fans come on. With or without aircon on.
    My understanding was that the passenger side fan turns on when the aircon is on.

    So far, I *think* ive checked the plug on the fans. By that I meant i pushed the plugs on the porcipine silver thingy (technical i know...) back in. I read a post somewhere about that.
    This didnt appear to help...

    Perhaps thermostat? Im not sure if this controls the fans or just opens / closes the water flow.
    Is there a simple way of testing this? I know that my heater is still working perfectly...

    Fan relay? This is the one in the middle of fuse box in the engine bay?
    Anyone know what part number it is? I'll just buy it today just in case...if i can

    Anything else that i should check?

    Thanks guys!!!

    p.s. - I cannot guarantee that the fans have been working since i installed C.O.P...(2 weeks ago...hadnt noticed either way...definately wasnt boiling over)
    I need to double check if something else is still unplugged, but checking this morning it all seems fine.
     
  2. VOLK

    VOLK Stabbin' technique!

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    Sounds purely electrical. Thermostat doesn't control fans. AFAIK ECU controls fans. Evoscan can trigger the fans, if they don't power up then electrical fault as suspected.
    If fans trigger then check wiring for water temp gauge unit and water temp sensor at thermostat housing but I don't think this is your issue...
     
  3. naughtika

    naughtika OzVR4 Stalker Moderator Trader

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    both fans turn on when a/c's turned on just not full on..

    also when you hit the temp where the fan triggers on.. its slow speed as well..

    best way to check is get someone who's got evoscan v2.6 and cable, use them to turn on the fan manually via actuators..

    if they turn on, then it might be your temp sensor..

    if they dont turn on then it might be your radiator fan resistor


    also.. this would be the first one if the COP install caused the issue.. so please let me know how it turns out..

    when was the last time you have changed your coolant?
     
  4. noony

    noony Hesitantly Boosting

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    Thanks guys
    Hopefully I can figure it out this afternoon.

    Lol - it won't be the COP. More likely to be that I bumped something during the install etc. On the cop front it's been good. Will know more after I fix this and my boost leak!
     
  5. noony

    noony Hesitantly Boosting

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    Oh and coolant was 6 months ago when I replaced the radiator
     
  6. BCX

    BCX 1 AYC Bar Premium Member

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    As stated before... the silver thing on the main rad fan is a power transistor as the ECU uses PWM to control fan speed.

    So if your fans aren't coming on, i'd be checking the following (some already covered by VOLK and naughtika):
    • Rad Fan fuse in main fuse box - engine bay - check for power at plug wire where power transistor is (fat blue wire)
    • Temp sensor (the one with two pins in the plug) - unplugging this should make the fans go flat out as ecu will think car is running hot (i'll check this when i get home)
    • Evoscan (although poorly implemented) can get the ECU turn the fans on full for a few seconds. Requires openport 2.0 or 1.3 cable too.
    • When A/C ECU drives compressor, the signal is fed into ECU to drive the fans. There is also two signals from memory - full and half depending what temp you have set on your climate control. If you dial it to 17 degrees and have it on full a/c (not eco) - fans should be on while motor is ticking over
    • Both fans are electrically joined in parallel - so both will turn on when ecu send PWM signal

    Will post more when i get home.
     
    eyeballprawn and VOLK like this.
  7. VOLK

    VOLK Stabbin' technique!

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    Nice work Bill, that's a comprehensive list and good explanation!
     
  8. noony

    noony Hesitantly Boosting

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    That is really good information! Thanks!!

    Everything looked in order so I replugged the 3 connectors on the silver thing again and it started working.
    I'm thinking it was the plug on the drivers side of it that was loose. Although it felt fine the first time.

    Bit of a worry, wonder if it will happen again...
     
  9. naughtika

    naughtika OzVR4 Stalker Moderator Trader

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    glad to know its sorted..

    but monitor your temp...

    also might be wise to replace your thermostat and coolant again..
     
  10. noony

    noony Hesitantly Boosting

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    Im going to book it in for a flush and pressure test, I'll get them to do that as well.

    I'll be checking out that Gauge thread and see what people are preferring at the moment.
    Would love to know the temp instead of 'yea, its about the middle of the gauge'. lol
     
  11. noony

    noony Hesitantly Boosting

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    well...spoke to soon
    determinately an intermittent problem. Temps started rising when stuck in traffic today and i realised the fans were not on.
    Quick rip down a side street and take the long way to work to get work and it cooled down as soon as i was moving.

    Im going to try this one this afternoon, hopefully those fans kick in like BCX suggested. Will obviously have to dig out the multi and do some probing around.

    Temp sensor (the one with two pins in the plug) - unplugging this should make the fans go flat out as ecu will think car is running hot (i'll check this when i get home)
     
  12. noony

    noony Hesitantly Boosting

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    I unplugged the temp sensor as suggested, didn't seem to do anything. Fans didn't kick back to life at all.
    I also looped the two thinking that would be the same as the sensor hitting it's 'on' temperature and creating a circuit. Also nothing...

    I did notice though that the fans do fire up when I first start the car. Only for a second or two. This happens no matter what I do with the sensor connector.

    My multimeter appears to have gotten legs...so I couldn't test the relay as I want wanted.
    Another task for tomorrow.


    Sent from my iPad using Tapatalk HD
     
  13. noony

    noony Hesitantly Boosting

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    Thought I'd update this for future reference...

    My fan saga continues!

    I took the beast into a radiator / autoelectrician place.
    The porcupine fan controller is shagged...
    They quoted me nearly $1k for a new controller and motor from Mitz. I laughed evily and said hell no!

    Took the controller off and had a good look at the terminals. The neutral is burnt out and melted. So it's obviously had a failure.

    Im thinking i may look at getting a new 14" and 12" instead of a second hand thermo. I'm undecided as yet.

    If I went down the generic path, I'm just unsure how the magic happens...
    Does the smaller middle wire on the thermo loom send the on signal for both aircon and temp sensors?
     
  14. BCX

    BCX 1 AYC Bar Premium Member

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    You'll still need the power transistor/controller. Middle wire is pwm output from ecu.
     
  15. fieldy107

    fieldy107 1 AYC Bar

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    Surely could find a second hand controller for cheap
     
  16. noony

    noony Hesitantly Boosting

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    Yea, someone local has a legnum wrecking. They are checking if the thermos intact.

    On the plus side...I cleaned all the burnt crap off the plug and connector. And...now it's working

    Wondering if it's simply melted cause it wasn't earthing well. Now that it's earthing it's working?
    :-s
     
  17. fieldy107

    fieldy107 1 AYC Bar

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    When things start working I stop asking questions and hope they just keep working lol :p
     
  18. noony

    noony Hesitantly Boosting

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    Lol
    Procrastination often wins...just not sure how long for this time
     
  19. naughtika

    naughtika OzVR4 Stalker Moderator Trader

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    got it sorted yet?

    if not.. can I suggest something else?
     
  20. noony

    noony Hesitantly Boosting

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    It's holding out for the moment...

    Always open for suggestions.
     

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