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Radiator fan direction

Discussion in 'Gen 2 Prius Main Forum' started by DaveWave, Mar 26, 2014.

  1. DaveWave

    DaveWave New Member

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    I bought my 07 salvaged (but already fixed) w a front end collision. After driving up a mountain road, it overheats. I checked it out and the radiator and condenser fans are both blowing out through the grill. This is counter intuitive and surely must be due to swapped wires, but after checking the wiring diagram both motors get their power well upstream from each other. Hard to believe they could have wired both motors backwards. Can someone confirm air flow direction for me?
    Thanks
     
    #1 DaveWave, Mar 26, 2014
  2. Mike500

    Mike500 Senior Member

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    Since they both are blowing in the wrong direction, the wires were reversed at some point after the fan relay.

    The repair personnel were probably NOT electricians but body technicians.

    It can happen easily, when they used butt spices.

    It would be easy to find the blue barrel insulated butt splice and replace them connected in the proper polarity.
     
    #2 Mike500, Mar 26, 2014
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  3. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Yes, the air flow clearly has to be so that the fans are sucking air from the grill. This problem has been reported by some other owners who had front-end work done - poor workmanship on the part of the tech who repaired that area.

    Can you reverse the fans so that they operate correctly?
     
    #3 Patrick Wong, Mar 26, 2014
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  4. Mike500

    Mike500 Senior Member

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    It's a very easy fix.
     
    #4 Mike500, Mar 26, 2014
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  5. Britprius

    Britprius Senior Member

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    It is not that the fans that are wired wrongly. The fans counter rotate, and if new fan blades are fitted they must be fitted to the correct side of the car. Leave the wiring and the motors where they are. Remove the fans off the motors and swap the positions of the fans. You will find the two fans have different numbers of blades "from memory one has six the other seven", and are designed to run in opposite directions. This will cure the problem.
    Do not reverse the wiring connections. This will make the fans blow in the correct direction, but they will be noisy and inefficient because the blades are airfoil shaped to make the as quiet as possible, this is also the reason for the different number of blades.

    John (Britprius)
     
    #5 Britprius, Mar 27, 2014
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  6. Britprius

    Britprius Senior Member

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    I should also have pointed out the wiring to the fans is more complex than most people would think. The fans can run in three configurations:- (1) Engine rad fan only full speed (2) Engine rad fan and condenser fan half speed (both motors in series) (3) Both fans at full speed. These operations are controlled by three relays.

    John (Britprius)
     
    #6 Britprius, Mar 27, 2014
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  7. DaveWave

    DaveWave New Member

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    Thanks guys. John, think you're right. Wiring for each is separate according to the schematics, so that didn't seem likely (didn't see any butt splices or tape either). At first I thought the fans might be on backwards but they can only go on one way. I did consider swapped fans, but iwas thinking these are probably one assembly and surely designed to fit one way... Will post after I look at it.
     
    #7 DaveWave, Mar 28, 2014
  8. Britprius

    Britprius Senior Member

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    Dave the fan motor shafts are identical so that the fans will fit on either motor.
    The fans them selves are made of a hard plastic that snaps easily braking off blades in an accident, and they are available as spare parts.
    Looking from the front of the car towards the rear the fan on the right should have five blades "not six as my first post, but I did say from memory" the one on the left seven blades. This should tie it down for you.

    John (Britprius)
     
    #8 Britprius, Mar 28, 2014
  9. DaveWave

    DaveWave New Member

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    Thanks, John, I'll dig in there to take a look shortly. Looking from the front of the car, the condenser fan (right) spins counterclockwise and the radiator (left) clockwise. Could any of you swell chums confirm this for me?
     
    #9 DaveWave, Mar 28, 2014
  10. Britprius

    Britprius Senior Member

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    I believe that is correct "again from memory" and you know what that's like.

    John (Britprius)
     
    #10 Britprius, Mar 28, 2014
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