01 Accord alarm/security, where to read wireless lock and unlock?

Discussion in 'Accord' started by ethan, Jan 12, 2005.

  1. ethan

    ethan Guest


    Does anyone know where I might be able to read the wireless FOB
    information? I'm basically looking to get indication when the keyless
    "lock" command is received, as is the keyless "unlock" command.

    I plan to run the signals into electronics for a project. If I were
    to simply grab the 12vdc going to the lights, that would be no good as
    it would be triggered at other times.

    Hopefully it can be had under the dash?

    Is there a module the controls the locks, and has separate inputs for
    lock and unlock and trunk from the wireless receiver?

    The more I think about it, a module to detect rain and roll up
    windows/shut sunroof would be handy also.

    ethan, Jan 12, 2005
  2. ethan

    Randolph Guest

    I don't know the specifics of the 01 Accord, but in recent vintage
    Hondas the receiver is integrated with the door lock control module.
    Thus the lock and unlock signal pulses may not be easily accessible. You
    could read the door lock actuator wires instead. Each actuator has two
    wires (well, two wores that count, some times there are additional wires
    for switches inside the actuator), applying 12 V with one polarity
    unlocks, the other polarity locks. Tapping into these wires in the
    driver's door will work (any other door may not, since with the priority
    unlock feature it is possible to unlock the driver's door only, the
    remaining actuators will not se any action). In the old days, the
    actuator wires were accessible under the dash as well, on the '01 the
    signals may (and I don't know if this is the case) be multiplexed onto a
    bus going into the door, and thus hard to access.

    Typically both actuator wires are grounded at rest, and lock and unlock
    is done with a positive pulse on one lead or the other. Pulse length is
    usually on the order of 0.5 - 1.0 seconds. You could tap into the wires
    directly, or you could use two polarized opto-couplers, one in each

    There is a Haynes manual for the 98 - 02 Accord (#42014). They usually
    have decent wiring diagrams. I have found Haynes manuals at several
    public libraries.
    Randolph, Jan 12, 2005
  3. ethan

    Seth Guest

    Actually, unless things have changed recently, Honda lock wires are ground
    activated. Meaning that they lock (or unlock) when ground is applied to the
    control wires. IIRC, they are light-blue and white and located behind the
    drivers kick panel.
    Seth, Jan 21, 2005
  4. ethan

    Randolph Guest

    Yes, the control wires are ground activated, but the control wires are
    not the ones driving the actuators. The actuators are driven with 12
    Volts, negative one side positive the other for lock, reversed for
    Randolph, Jan 21, 2005
  5. ethan

    Seth Guest

    And for what he's looking, in my opinion, that is over complicated. The OP
    just wants a "signal", one for lock and one for unlock. The control wires
    do just that, already separated by function (lock/unlock) and are low
    amperage, perfect for connecting directly to a logic circuit for activation
    detection. That's why almost all car alarm manufacturers go for these wires
    and not directly to the actuator wires.
    Seth, Jan 21, 2005
  6. ethan

    Randolph Guest

    Absolutely, the signal wires are the easiest to use, if they are
    available. With the remote receiver built into the door lock control
    module, the signal wires may not be available externally. If you gave
    specific information to the contrary, the OP would probably be happy to
    hear it.

    The actuator wires not difficult to use. In most cars, with the system
    at rest, both wires are grounded (not left open). The functions are
    separated, a positive pulse on one wire means lock, a positive pulse on
    the other means unlock.

    If the OP wants info from the remote control only, sensing the actuator
    wires will not work. Sensing the actuator wires, you will get the same
    lock and unlock signals no matter what caused the lock or unlock (key,
    manual switch, remote control etc.).

    The current flow in the wires is of no consequence. If there are 25 Amps
    or 5 milliamps, the logic circuit would still just sense a 12V signal.
    Randolph, Jan 21, 2005
  7. ethan

    ethan Guest

    Much thanks everyone for the info. I could probably use use an
    optoisolator + resistor tied to each one of the lock leads to alert the
    embedded computer as to power headed for the door solenoids.

    Is the lock module on the passenger kick panel? I found that module
    when running some other cables.
    ethan, Jan 25, 2005
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