Miata Mailing List: September 1999, Message #345

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Hi Gang,

Since several people have asked for the instuctions for the flasher
modification for the center brake light I'm forwarding the write-up I sent
in to the Greater Cincinnati Miata Club newsletter.  If my explanation is
not as clear as it should be e-mail any questions to me.  Good Luck.

As Ruth and I approached Knoxville, TN on the way home from Deals Gap I
overtook some other Miatae, and when we slowed for a stoplight I noticed
that on one of the Miatae the center brake light flashed when the brakes
were applied.  Being the clever fellow that I am I immediately recognized
a cool mod that I had to pursue.

In order to ascertain what information was available for this I checked
with the Miata electronics wizard, Jeff Anderson.  He told me of an
acquaintance of his that had obtained a flasher from MM Marketing which
had a unique flash sequence (three short and one long flash per cycle), so
I checked their website for information, but without success and then
e-mailed them.  They never responded. So I decided to do a little
experimenting on my own.

I stopped of at an Auto Zone to see what kind of flashers they had.  The
dim bulb who tried to help me didn't seem to know what a flasher was, but
he did lead me to the right aisle.  There I found a Tridon 12 volt, 2
terminal, standard duty, turn signal or hazard warning flasher, #
536/552-C.  This is a small thermal flasher designed for 3 lamp turn
signals or 6 lamp hazard warning (as stated on the back of the package)
and has two spade lugs.  It cost $1.80 plus sales tax, and  looked to me
like exactly what I needed.  It certainly wasn't going to cost much to
try.

Note to those who are going to perform this mod: When your at the auto
parts emporium it is a good time too pick up some crimp on terminals to
fit the flasher if you don't have any.
  
When I got home I opened Drifter's trunk and popped out the center brake
light socket from its housing, I removed the bulb from the socket and
temporarily connected it and the flasher to my battery charger to see how
it worked.  The light blinked at about once per second and it was on about
as long as it was off.  This was not as fast as I would have liked, but
for $1.80 one cannot expect to have all of his prayers answered.

So I decided to forge ahead. The center brake light is connected to two
wires, one black (power) and one  green (ground).  The flasher can be
spliced into either wire, but to reduce the possibility of a short circuit
it is better to splice it into the ground wire.  (This didn't occur to me
until after I installed the flasher so I spliced it into the black wire.) 

I pulled a little slack out of the loop at the hinge (so I had some wire
to work with), trimmed about four inches off the black plastic sleeve over
the conductors adjacent to the light fixture and cut the green conductor
about two inches from the socket.  I stripped 1/4" insulation from each of
the cut ends and crimped a spade lug terminal onto each.  Then I plugged
the flasher in and put the socket back into its housing.  I slipped a
piece of pipe insulation over the flasher and stuffed it into the recess
where the brake light is, and that was it except for a test.  The easiest
way to see what you have accomplished it to get someone else to step on
the brake pedal while you stand at the back of the car and proudly watch
the results of your labors.  What I did was take my Club (anti-theft
device) and position it against the seat so it depressed the brake pedal. 


Needless to say everything worked as I expected.  A subsequent masurement
revealed the the
flash rate was about 61 flashes per minute.

The only drawback for this mod is that you'll want to step on the brake
more often to show off your cool flashing brake light and of course you
can't see it yourself.

Note: There probably are other inexpensive flashers produced by other
manufacturers and sold under other brand names found in car parts
departments in places like Walmart which work just as well or better than
the one I found.  These things are pretty simple devices which heat up
when the current flows and the heat opens a contact which disconnects the
load.  When it cools off it turns the light back on.  If you find one
which is rated for a smaller number of lamps it will flash at a faster
rate and conversely one rated for more lamps will flash at a slower rate.

This is a very inexpensive and simple modification that is not only kind
of cool, but it attracts more attention to you when you are comming to a
stop.  I wish I knew who to thank for leading the way.

Bill Bowser & Drifter
Black & Red '93 LE
  Cincinnati, Ohio