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Where is the hood switch?

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by chych, Jul 10, 2014.

  1. chych

    chych Junior Member

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    I'm trying to find the hood switch in my 2005 Prius but I'm not able to locate it. Can anyone tell me where it is?

    This comes from a problem I'm having where the factory alarm is randomly going off, but very intermittently (weeks between events). I'm thinking if I make the car think the hood is always open, by disconnecting the hood switch, then the alarm won't arm. Went to the dealer and they couldn't find anything wrong...
     
    #1 chych, Jul 10, 2014
  2. JC91006

    JC91006 Senior Member

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    what factory alarm do you have? I don't recall there being an alarm from the factory, maybe a dealer add on. You should check your 12v battery, make sure it's not low
     
    #2 JC91006, Jul 10, 2014
  3. Patrick Wong

    Patrick Wong DIY Enthusiast

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    I agree that the 12V battery condition should be checked.
     
    #3 Patrick Wong, Jul 10, 2014
    Last edited: Jul 11, 2014
  4. chych

    chych Junior Member

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    The 12 V battery checks great, high voltage and everything. Dealer did all the standard checks as well. The factory alarm in the Prius (all Prii have this) is the one where it honks/flashes if a door becomes unlocked or opens, without using the key, after it has been armed. The alarm arms after all doors (including hood) are closed, and all doors are locked. You can test this by keeping a window open, locking all the doors, waiting a minute, and unlocking a door through the window (and the Fob is not near the car). There is red symbol on the dash that goes solid; when it is solid, that means the alarm is arming. Afterward a short time, it flashes, and the alarm is armed.

    In any case, I did find the hood switch, it was right in the hood latch assembly, underneath the plastic cover. Actually it's not a mechanical switch, looks like a magnetic one. When unplugged, the Prius will always think the hood is closed. So in the end I actually had to short the two pins of the cable (with a paper clip), and now the Prius thinks the hood is always open. As a result, the alarm will not arm, as the red light on the dash never goes solid after the doors are locked. Alarm defeated!

    I did a lot of internet searching for this problem of the alarm randomly going off, and found little in terms of a good solution. For some, it was the battery, others it was the Key Fob acting up, and others like me, unexplainable. The hood switch solution seems to be one way to resolve this, I hope!
     
    #4 chych, Jul 11, 2014
    Michael Warren and Patrick Wong like this.
  5. Mark Serlin

    Mark Serlin New Member

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    Did you try just unplugging the cable so the car always thinks the hood is shut, leaving you the benefit of an alarm on all the doors/windows, at least? Maybe there was nothing wrong with the hood switch and replacing a door switch would do it?
     
    #5 Mark Serlin, Oct 15, 2015
  6. KyleSTL

    KyleSTL Junior Member

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    I had a problem similar to this on my Volvo V70 wagon for the trunk switch. Over the course of years the switch had so many on-off cycles that occasionally (temperature changes, moderate winds, etc) would cause the switch to lose contact and the alarm would go off. I was able to correct the problem by taking apart the latch mechanism and bending the arm of the switch slightly so the electrical contacts had more pressure on them when they were in the closed position. Is there any indication this could be the cause on the trunk hatch or possibly one of the doors (like driver's side door)?
     
    #6 KyleSTL, Oct 15, 2015
  7. edthefox5

    edthefox5 Senior Member

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    I'm confused. Why not just not arm it? Use mechanical button to lock door on the way out.
     
    #7 edthefox5, Oct 17, 2015
  8. Alecjoel

    Alecjoel New Member

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    I am having this same problem! I think I found the switch but I don't want to mess up the wrong thing. Any chance you could give me some specifics so I can do the same thing? Thanks!
     
    #8 Alecjoel, Mar 12, 2016
  9. valde3

    valde3 Senior Member

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    There’s only one electrical connection on the hood latch. So once you remove the plastic panel above the radiator it’s very self-explanatory. My Prius doesn’t have factory (or aftermarket) alarm so there’s nothing connected to that switch.
     
    #9 valde3, Mar 13, 2016
  10. Michael Warren

    Michael Warren Junior Member

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    I just did this and hope it works on my 2008 Prius. I had a 2007 Prius several years ago with the same problem but can't remember how I fixed it. I know I pulled the horn fuse for awhile but that doesn't keep the lights from flashing and eventually draining the battery.

    After shorting the pins with a paperclip in the (white/female side) latch switch, my red car/key light on the dash continuously blinks, never going solid. This means success right? Alarm isn't arming?
     
    #10 Michael Warren, Apr 19, 2022
  11. mr_guy_mann

    mr_guy_mann Senior Member

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    If your alarm stops sounding off by itself, then I would say yes. May want to consider putting some silicone grease around the connector and paperclip so it doesn't corrode.

    Posted via the PriusChat mobile app.
     
    #11 mr_guy_mann, Apr 20, 2022
  12. Stormy Steve

    Stormy Steve Junior Member

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    Thanks for Ralph Nader.
    Just more stuff to break!
     
    #12 Stormy Steve, Sep 15, 2022
    bisco likes this.
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