Car radiator fuse blown

Discussion in 'General Electronics Chat' started by Lanz, Oct 2, 2010.

  1. Lanz

    Thread Starter Active Member

    Oct 30, 2008
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    My fren's car radiator fan fuse always blown.The temperature rise up.Im wondering what cause that.Anybody faced the same problem?What might be the cause and solution?
     
  2. awright

    Well-Known Member

    Jul 5, 2006
    84
    7
    Does the fan blade spin freely? Have you measured the fan current at maximum battery voltage and compared it to the fuse rating? There should be some headroom between the fan current and the fuse rating. I'm not sure how much, but 50% might be reasonable.

    Have you checked the condition of the fan wiring? Have you checked the condition of the brushes in the fan motor (assuming they still use brush motors).

    If everything checkes out, maybe you have to change your fan motor.

    awright
     
  3. Rbeckett

    Member

    Sep 3, 2010
    205
    32
    Unfortunately most radiator fan fuses blow due to high amp draw from bad bearings or melted windings inside the motors. I have replaced many many of them as an auto mechanic. I would insure the coolant is full, allow the vehicle to idle and see if it cycles on and off in the correct range. If not, start looking for the draw from the fan. The bad news is they are relatively expensive unless a universal motor replacement kit is avilable for your year, make, and model. There are some out there, but not for all. Sorry.
    Bob
     
  4. Lanz

    Thread Starter Active Member

    Oct 30, 2008
    153
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    Thanks for the info guys.I will consider that.But now im thinking to do a circuit to give warning to the user if the temperature rise.Something like a comparator connected to the temperature gauge.A LED and a buzzer as warning indicator.As soon the temperature rise from normal temperature,the comparator circuit send the signal to the LED and the Buzzer.So...anybody had did something like this.Please share your experience and knowledge so that i can move further.;)
     
  5. campeck

    Active Member

    Sep 5, 2009
    194
    3
    there should already be a temp gauge in the car right? What's an LED and buzzer going to do? There still isn't going to be a functioning fan...
     
  6. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    Cars are already equipped with either "idiot lights" and/or gauges. If the driver does not pay attention to their instrument cluster, it's their fault if they overheat the engine.

    I don't recommend attempting modifications to the instrument cluster. Odds are very high that modifications will fail pretty quickly, even if the builder is a pretty experienced hobbyist.
     
  7. Lanz

    Thread Starter Active Member

    Oct 30, 2008
    153
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    Yes,u both are correct.You can only notice the temp rise if you looked at the gauge.How if you forgot to watch the temp gauge or you busy concentrating on the road or talking to the passenger?But you can save your engine from overheating if you got a flashing LED or a buzzer.I think not all cars has "idiot lights" as mentioned by Sgtwookie especially old cars or modified cars.
     
  8. marshallf3

    Well-Known Member

    Jul 26, 2010
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    Fans are cheap and easy enough to replace, there's even universal ones on eBay.
     
  9. Jaguarjoe

    Active Member

    Apr 7, 2010
    770
    90
    Plucking a signal from the existing temperature sender could be problematic. It is far from linear. How will you know what to make your overtemp limit setpoint?

    Maybe this could help:

    http://tinyurl.com/27avjhr
     
  10. Lanz

    Thread Starter Active Member

    Oct 30, 2008
    153
    0
    Yeah...fans are cheap but do engine or engine parts and radiator cheap?What im trying to do is prevention....if only fan affected coz temperature rise means ok....but engine will get overheated.Do you got what im trying to say?

    Yes...it could be problematic...so this circuit should be added as an extra circuit with fuse protection or etc so that wont effect the car.For linear problem....got to do linear converter circuit and for the setpoint....can put potentiometer to adjust and calibration.[​IMG]But i dont know wether this can be achieved or not.
     
  11. marshallf3

    Well-Known Member

    Jul 26, 2010
    2,358
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    The thing is if the fan is blowing a fuse then there's a problem there and 99% of the time it's the cheap fan motor itself going out.

    You can put warning lights all over the place but what good is a vehicle if you have to pull over every now and then to wait for it to cool down, only to go a few more miles if the fan hsn't started working again?

    And all it takes is one large overheat (or several minor ones) before your head starts to warp - then you're talking big $$.

    Fix the fan first, then if you must you can go about tapping off one of the temp sensor signals or possibly gluing an LM35 IC to the side of the radiator. Another even easier option would be to buy one of those bi-metal thermostatic switdches from eBay, something that's operates when it reaches 100*C or something like that and have it power anything you want.
     
  12. t06afre

    AAC Fanatic!

    May 11, 2009
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    I have to agree with what other poster say. Without a fan your cooling system will not work properly. And without a proper cooling system your engine will sooner or later be damaged. Most probably sooner than later. The engine overheat because the fan is not working hence blowing the fuse. The problem is not that your fan stop working because the engine is overheated.
    By the way are you sure you are using the correct fuse. If the fuse for some reason have a to small rating. This may be the result. Check if your car has a aftermarket fan that may require more current than the original fan.
     
  13. Ron H

    AAC Fanatic!

    Apr 14, 2005
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    Maybe what Lanz is saying is that even if he replaces the fan, he still wants an idiot light. That would probably be a good idea.
     
  14. Jaguarjoe

    Active Member

    Apr 7, 2010
    770
    90
    Here is an adjustable temperature switch that attaches to the radiator and can be adjusted up to 248 F. Sensing the radiator temperature will provide the earliest warning that the cooling fan failed.

    http://www.summitracing.com/parts/HDA-3653/
     
  15. Lanz

    Thread Starter Active Member

    Oct 30, 2008
    153
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    Yes...what u said is true.Maybe if ur engine is not that overheated...but there is a possible that other parts been damaged cause high temperature.

    I had checked the fuse...its correct.And the fan also in good condition.I suspect maybe the wiring is the cause.

    Yeah....warning light is good but a buzzer is better.Sometimes you forgot to look at the temp gauge.So in this situation a warning indicator can remind us to look at the gauge.Thats what im trying to say.

    Thanks for the link joe[​IMG]
     
  16. Lanz

    Thread Starter Active Member

    Oct 30, 2008
    153
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    Guys i know fans are cheap.But not the fan only be a problem if the temp rise.It can be the water pump failure,less water in radiator,radiator leaking,no coolant n etc.What im trying to say is...not all driver used to watch the temp gauge.Lets say...the temperature gauge shows the temp rise than normal level.The driver didnt watch the gauge because busy concentrating on the road.What will happen?Lets say the driver is on a long journey and the car breakdown because of this.Its annoying and a big problem rite.At least with this circuit the driver may know that the temp rise from normal level and he could take some steps to prevent from overheating such as.....driving slowly till reach any workshop.As i know...modern cars have warning lights...at least has warning indicator.
     
  17. retched

    AAC Fanatic!

    Dec 5, 2009
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    ...Driving slowly.... funny...

    Tell that to my brother.

    We were overheating coming down 83 (A baltimore highway, quite busy) and he decides:

    "Well, the engine is overheating, so lets get some air over the engine!"

    Guess how he decided to do that....

    I think a tazer would work better than a buzzer ;)
     
  18. t06afre

    AAC Fanatic!

    May 11, 2009
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    I have a a garage princess. It is 21 years old. Then I take out for a spin. I can assure you that I keep a close eye on both water temperature, and oil pressure. If some of them is outside normal range, I will stop the engine asap. To get a tow truck will mostly be covered by my assurance, and it will cost peanuts compared to rebuild a V12 engine:eek:
     
  19. marshallf3

    Well-Known Member

    Jul 26, 2010
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  20. shortbus

    AAC Fanatic!

    Sep 30, 2009
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    Why not use the feed wire that turns on the temperature light to trigger a relay to turn on the buzzer?
     
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