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Blowing From Back Vent(AC off)

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Spenny, Jul 30, 2015.

  1. Spenny

    Spenny Member

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    Hey,

    My vehicle is having an issue and luckily it's still under warranty. I know I could leave all the troubleshooting to Toyota but some of my dealer's mechanics do not seem to be that great at troubleshooting issues.

    For the past year I would ocassionally hear a wind noise from the backseat on the passenger's side. It seemed to coincide with acceleration so I figured that a seal had come loose. I took it by the dealership but they couldn't figure out what was wrong. A few days later, I heard the same noise but for the first time ever, it actually got louder when I was stopping so I figured out that it wasn't a seal. I was lucky enough for the issue to keep going even when I parked so I found out that it was air being forced out from the A/C system(from vent near the seat cushion).

    Any idea what would cause this? I almost might think something wasn't grounded properly. I had another weird issue like this(not air but intermittent) on my old Jeep and it ended up being a grounding issue.


    Any ideas?
     
  2. Air_Boss

    Air_Boss Senior Member

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    Battery cooling fan. Check to see whether the inlet is jammed up with lint and the fan is interference free.
     
  3. JC91006

    JC91006 Senior Member

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    it's the fan to cool your hv battery. Your car must've been hot? Or you've just gone downhill for 10 miles and overcharged the system
     
  4. Spenny

    Spenny Member

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    I actually did find a post about the HV fan. I'm just wondering if it's working correctly.

    The post I found seemed to indicate that it sucked air from inside the cabin to the battery. Is that true? I ask because it was blowing and it was blowing very hard. It was a really hot day but I had traveled less than 1 mile.
     
  5. Mendel Leisk

    Mendel Leisk Senior Member

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    Are you sure air's blowing OUT? And that's at the small grill at bottom-corner of rear seat back?

    Air should be sucking into that vent, not blowing. If it is actually blowing, that's the hybrid battery cooling fan, moving air in wrong direction.

    If it's in fact sucking air in, still could be a concern, indicating battery is running hot.
     
  6. Spenny

    Spenny Member

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    Yeah, it was definitely blowing. I figured it was a regular air vent because it was blowing cool air.

    I wonder if there's a way the fan can be put in backwards? Maybe that would explain the blowing.
     
  7. bisco

    bisco cookie crumbler

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    i wouldn't drive it until you figure it out. do you carry any pets? how hot is it where?
     
  8. Former Member 68813

    Former Member 68813 Senior Member

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    no, check again.
     
  9. rjparker

    rjparker Tu Humilde Sirviente

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    I have seen the AC in normal mode (not recirculate) blow open window seals enough to make noise, particularly with a higher fan speed. Lowering the fan speed or placing the AC system in recirculate stops the noise.
     
  10. Spenny

    Spenny Member

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    I had my hand on the vent. It's possible it was back pressure but there was air blowing out toward the cabin.
     
  11. bisco

    bisco cookie crumbler

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    yes, you can feel some air movement. put a tissue over it and see if it sticks or is blown off.
     
  12. RRxing

    RRxing Senior Member

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    Assuming it's a DC blower motor, is it possible the leads were reversed? Did you get the car new or used? Was any sort of maintenance done on or around the traction battery or back seat? I know, so many questions...
     
  13. Spenny

    Spenny Member

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    I'm not sure what kind of motor but if so, that is a possibility. I did get my bumper replaced in back but I'm not sure what needs to be removed for it to be replaced.

    It was blowing. I felt the air come outwards. I know sucking will also cause a cooling effect but I know the difference.
     
  14. bisco

    bisco cookie crumbler

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    perhaps the exit is blocked.
     
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  15. Spenny

    Spenny Member

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    Any idea where the exit is located?

    I normally buy a Haynes on any car I buy but I haven't since it's still under warranty.
     
  16. bisco

    bisco cookie crumbler

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    there are threads here with pics of the whole assembly, or google it for video's. it travels under the deck from the grille to the battery box, then exits in the 12v area, iirc.
     
  17. RRxing

    RRxing Senior Member

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    Correct - then the air exits the vehicle through louvers on the left and right (12V battery) side:


    HV Battery Exhaust Vent.jpg
    It's possible that when the rear bumper was replaced the right side louvers were blocked or otherwise prevented from opening to let the air out, allowing it to back flow. In any case, the rear bumper replacement was our best clue... Good luck.

    NOTE: The louvers are not visible from outside the vehicle, they're behind the bumper...
     
    #17 RRxing, Jul 30, 2015
    Last edited: Jul 31, 2015
    bisco likes this.
  18. Spenny

    Spenny Member

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    Thanks. I'll have to figure out what to do next. I guess that's the most likely scenario since it's blowing into the cabin.

    Is there any case to made for damages? I worry that some of the components may have premature wear because they weren't cooled as designed.
     
  19. Air_Boss

    Air_Boss Senior Member

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    Rhetorically, why does 'Is there a case to be made for damages' perennially come up among the first questions?
     
  20. rjparker

    rjparker Tu Humilde Sirviente

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    If you did the tissue test to verify air flow, then go to dealer, do not pass go. No battery cooling could cause lots of damage so you need to "trust" the mechanics. They do know what they are doing, you are under warranty and you might have a tough timing proving anything tthree years from now when and if your expensive battery dies.