1. Attachments are working again! Check out this thread for more details and to report any other bugs.

Push to start button killer.

Discussion in 'Newbie Forum' started by Flagmaster, Feb 19, 2017.

  1. Flagmaster

    Flagmaster Junior Member

    Joined:
    Aug 26, 2014
    70
    12
    0
    Vehicle:
    2012 Prius
    Model:
    I
    This might sound kinda silly, but Im trying to figure how the best way to "dissable" this button for a alarm install.

    Because I already have to carry the alarm key fob with me, I dont want to have to carry the Toyota key fob with me as well. So what I did was take the Toyota key fob apart, removed the battery, and took the little circut board out. I then zip tied this onto the push to start button part itself.

    This poses a security risk, in that the car will always "see" the key and thus anyone could just push the button at any time and start the car. (and this is true). So to prevent this, I cut a yellow wire going to the button. Im not 100% sure what that yellow wire does, but this did the trick. Now the push to start button is dead.

    Next, I took each end of that cut wire, and connected it to a relay. This relay holds the yellow wires in the non-connected state (open) when the car is armed. Once I hit the disarm button on my car alarm fob, the relay pops, closing the break--connecting the yellow wires back up, enabling the push to start button to see the Toyota key fob circut board zip tied to it---it starts beeping, Open the door, press the break, light turns green, push the button and go!

    So, here is the problem....

    The 12 volt battery gets drained down all night. The car arms, the "ground when armed" grounds, closing the relay (coil is connected to +12, and this ground-when-amred wire). This enegizes the realy and thus holds open the cut yellow wire.

    In this way, if someone breaks the window, sets off the alarm, and tries to press the button, it wont start.

    Im looking for a better way that wont use as much electrical power, enengizing a magnet in a realy all night long.

    My thought would be to "repair" the cut yellow wire, but also "Tee off it" to this ground when armed thru a resistor. The theory is that the data would be then "shorted to ground" and never reach the computer to unlock the start button. But I dont want to short out anything unless I know I wont damage anything.

    Thoughts?
     
  2. Flagmaster

    Flagmaster Junior Member

    Joined:
    Aug 26, 2014
    70
    12
    0
    Vehicle:
    2012 Prius
    Model:
    I
    Is the yellow the data wire? Or did I just get lucky in some other way?
     
  3. Mendel Leisk

    Mendel Leisk Senior Member

    Joined:
    Oct 17, 2010
    54,669
    38,209
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    Maybe leaving the fob in the car is going to run the 12 volt battery down? Not sure.
     
  4. Prodigyplace

    Prodigyplace Senior Member

    Joined:
    Nov 1, 2016
    11,696
    11,317
    0
    Location:
    Central Virginia
    Vehicle:
    2017 Prius
    Model:
    Two
    Since the battery is removed, I would suspect leaving the "fob" on the start button could cause RFID to drain the battery.

    Perhaps he needed to "cut the red wire"? :eek: :LOL:

    Top 10 Wire-Cutting Bomb Diffusing Scenes in Movies
     
    RCO and Mendel Leisk like this.
  5. Flagmaster

    Flagmaster Junior Member

    Joined:
    Aug 26, 2014
    70
    12
    0
    Vehicle:
    2012 Prius
    Model:
    I
    paste from another forum.
    --------------------------------------------------------------------------------------------------------
    The ground out when armed is only for starter kill relays and shouldn't be used for anything else. I wouldn't recommned using it to power a relay to supply power to any sensor. If you use it for this purpose the relay will be energized when the alarm is armed. The resulting draw of around 150 ma will kill a vehicle's battery in a day or so. Sensors should always be hooked up as the instructions say. They are almost always hooked to battery and constant ground. They only draw a couple of ma or so. Sensors also tend to trigger right after they are powered up, so it could cause false alarms when arming. It is important to understand that when using the ground when armed output it should only be connected to one side of the relay coil (Terminal # 85). The other side of the relay coil (Terminal # 86) MUST be connected to an ignition source and NOT to battery. This way the relay is only energized when the alarmed is armed and only when the ignition circuit is powered.
    ---------------------------------------------------------------------------------------------------------

    in my case, I am connected to the battery, and I am running the battery down in a day or so.

    I cant use IGN since the pirus wont generate that until the button is pressed---and the button needs to be dead and stay dead till dissarmed.
     
  6. hill

    hill High Fiber Member

    Joined:
    Jun 23, 2005
    19,666
    8,067
    54
    Location:
    Montana & Nashville, TN
    Vehicle:
    2004 Prius
    Model:
    IV
    Not if it's wrapped in foil or placed in a little metal container. That's been the trick over the past 13 years or so.
    .
     
    Mendel Leisk likes this.
  7. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    107,693
    48,945
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    i think you may be on your own.
     
    RCO likes this.
  8. Prodigyplace

    Prodigyplace Senior Member

    Joined:
    Nov 1, 2016
    11,696
    11,317
    0
    Location:
    Central Virginia
    Vehicle:
    2017 Prius
    Model:
    Two
    but you are referring to a fob with the battery installed. I believe they were referring to a fob without the battery fastened to the Start button. Behavior would be somewhat different,
     
    Mendel Leisk likes this.