Need help with a car gear shifter

Discussion in 'Automotive Electronics' started by Baller95, Sep 4, 2015.

  1. Baller95

    Thread Starter New Member

    Sep 4, 2015
    Hey guys, I have a disability which limits the use of my hands making it very hard for me to push the gear shift button. I have a wiring diagram of the shifter assembly below. I'm looking to put a momentary push switch somewhere near the shifter that I can push and that will timed to stay in the active position for about 5 seconds which'll give me time to change the gear. Don't think it's a good idea tapping right into the solenoid but the micro switch (Yellow & Dark Green/White wire) looks like it'll work. How should I go about doing this? Any help is appreciated!
  2. crutschow


    Mar 14, 2008
    You could use a one-shot timer, such as a 555 circuit to drive a relay, as shown here on the left near the bottom of the page, with the relay NO contacts connected in parallel with the microswitch (across the YEL and DK GRN/WHT wires).
    The values shown give a one-shot time of over 5 seconds (my simulation showed 5.3s).
    The relay can be any small 12V relay, such as an automotive type.
    The spike suppression diode across the relay can be any small type such as the common 1N4148.
    Last edited: Sep 4, 2015
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  3. KeepItSimpleStupid

    Well-Known Member

    Mar 4, 2014
    When I look at the ckt above, i think the following:

    a) The anti-theft system locks the shifter in park.
    b) Shift Park signal is the "ability to get out of park"
    This is usually generated by the brake pedal. i.e. You have to press the brake in order to get out of park.
    c) This has the added feature that the anti-theft system also prevents getting out of park.

    my car actually has a small cover about 1 cm x 1 cm, which when removed allows you to unloct the shifter wih what I presume to be a screwdriver. I never had it off.

    I did see one car in my life that had a push button transmission for each of PRNDL.

    Note, the module has access to the brake pedal position which can be used to re-affirm what i think is happening.

    "Barking up the wrong tree", perhaps? Those contacts in question are activated by the foot, not the hand.

    Easy enough to test too. Put a voltmeter across pins 2 and 19 and press the brake assuming the anti-theft system is un-armed.


    My mom has bad hands and she was unable to twist the ignition on the column of a vehicle she owned all the way to "start". For a while, there was a big pair of pliers in the car, until I could add a manual start push button. What a pain.
  4. Baller95

    Thread Starter New Member

    Sep 4, 2015
    Thanks, I'll look into that!

    Yeah there is a brake pedal position sensor which I'm assuming is somewhere by the brake pedal. The two contacts that I've listed for the microswitch looks like it's in the shift lever.
  5. JohnInTX


    Jun 26, 2012
    The ones I've messed with work this way except that I think Shift-Park is the signal to the computer that it can crank the engine when starting. It also would tell the computer to drop power to the solenoid after the shifter is moved out of PARK. There also is usually a connection to the ignition key capture system when its out of PARK.

    The brake signal indeed enables the solenoid to allow the shifter to be moved out of PARK. The little keyhole thing is a manual release in case the brake sensor fails (on a Honda, its the stoplight switch). It allows you to move the car but (in the Honda's case) the stoplights won't work.

    If the TS's shifter has a mechanical button, I still think he needs to squeeze it to move the shifter - even with the solenoid pulled in.

    Just my .01
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