From: hbarta@wwa.com (Henry C. Barta)
Newsgroups: rec.autos.makers.mazda.miata
Subject: Re: Headlight Aiming
Date: 11 Jan 1998 04:19:05 GMT

The following describes how I converted the key reminder buzzer to
a light reminder buzzer. I have no idea if this will work on your
car. I have no idea if it will cause damage to your car. If you
do this, you do this at your own risk. The worst thing that I can
think of happening is that you could start an electrical fire in your
car and burn it up.  (IMO, that would be pretty bad.) If you are not
comfortable working on the wiring on your car, do not try this. If you
do not understand electricity, do not do this. I do, and I might have
left something critical out that could cause you grief. When you make
connections be very careful that exposed parts of wires and connectors
are covered with electrical tape or, better yet, heat shrink tubing.
Otherwise a short later on could cause you problems, and electrical
problems can be some of the nastiest problems to fix in a car. (It
looks to me like the wiring harness is the first thing put in a
car, so you might have to remove an *awful* lot of stuff to get
to it should you smoke test one of the wires it contains.) Most
instructions for doing electrical work tell you to disconnect the
battery first. I did not because I wanted to take readings as I
went. Furthermore, I feel that I am at greater risk placing a wrench
on the hot battery terminal and turning it than working under the
dash. If you want to be safe, disconnect the battery before you
make connections and connect it temporarily when you want to take
voltage readings.

If you do try this, take a moment to let me know the results.
(hbarta@wwa.com) Also let me know what year car you have and anything
you did differently. As time permits, I will add your information to
this description and perhaps make it applicable to other year Miatas.

I did this on my '95 PEP with ABS brakes. Other cars, even other
'95s, might differ. Mine has the newer style interior fuse block
with the smaller fuses.

The idea is to change the input to the buzzer so that it reacts to the
lights on instead of the key in the ignition. The key switch feeds
battery voltage to the buzzer relay whenever the key is inserted.
I disconnected this and connected the buzzer input to the supply side
of the dash light dimmer switch instead. So, whenever the dash lights
are on (and since I used the input side, even if they are dimmed)
and the door open, the buzzer will sound. The dash lights go on in
both 'on' positions on my light switch.

The primary problem is locating the correct wires. I examined the
wiring diagram in the factory manual and the car, and when I
thought I had found the correct wire, I verified it by taking voltage
readings (using a digital multi-meter) during the various operating
conditions. It would be wise for you to do the same. 

    Locate the buzzer relay. This is under the dash on the driver's
    side and is between two other relays. I can feel it buzzing when
    the key is in and the door open. It is straight out from the
    front most screw that holds the fuse box in. It has a blue/yellow
    (blue with a yellow stripe) wire that provides battery voltage
    when the key is in the ignition.

    Cut the blue/yellow wire where you have enough space on either
    side to repair it if you desire. (Purists who have a problem
    cutting wires in their car can remove the panel under the steering
    wheel and remove the connector from the key switch instead.)

    Tape over the harness end of the wire (it will have battery
    voltage present whenever the key is inserted in the ignition)
    and prepare the relay end to connect to another wire. I used
    a crimp type butt connector.

    Contort your arms as necessary to reach behind the dash and
    squeeze the sides of the dash dimmer switch to be able to push
    it out of the dash. (It comes out toward the driver, not behind
    the dash.)

    The back of this switch has three wires connected to it. Viewing
    the connector (female side) from the switch side (as is the
    convention, I believe, in the shop manual) the pin outs are a
    shown below:

                     _________
                    |         |
                    | 1 xxx 2 |
                    |         |
                    | 3 4 5 6 |
                    |_________|

                1           red
                2           black
                3           NC (no connect)
                4           red/black
                5           NC
                6           NC

    (My thanks to Jeff Anderson for the prototype of the 'connector
    art' :)

    I used the red/black wire. It showed about 10 Volts with
    the lights on. The voltage on the red wire is reduced as the
    instrument lights are dimmed and the black wire is a ground.
    I spliced another wire into this wire using a ScotchLock. (This
    is a particular brand of connector. I'm not sure if that's the
    real name, but that's what I have always called them. They allow
    you to splice one wire into another with out cutting the wire you
    splice into.)

    The other end of the wire added in the previous step is connected
    to the relay end of the blue/yellow wire cut earlier.

Test the changes out. The buzzer should now sound when the parking
or headlights are on and the door is opened, regardless of ignition
switch position. When the lights are off, the key in the ignition,
and the door open, the buzzer should remain blissfully silent.

Hank Barta                              White Oak Software Inc.
hbarta@wwa.com                          Predictable Systems by Design.(tm)
                Beautiful Sunny Winfield, Illinois