GTV6/Milano speedo

["Don Happel" <zelatore@domain.elided>]

A while back I posted a note asking for help getting the speedo to work in
my GTV6 with a Verde transaxle.  Here's my solution to the problem.

Since the early sending unit for the GTV6 is different from the late
GTV6/Milano, you cannot use a combination of early and late parts.  I
switched all my components to late model parts and every thing is working as
of about 15 minutes ago when I went for a test drive.

The first part of this is the same info you will find at www.gtv6.org along
with photos.

You'll need the sending unit from the transaxle you are installing.  In my
case, a Verde unit.  You will also need the sending unit amplifier from the
same type car.  This usually lives under the rear seat on the driver's side.
You will also need a speedo from the same car.

I already had a sending unit in the transaxle, so all I needed was the
speedo and the amplifier.  A quick trip to APE yielded these items despite
there insistence that it wouldn't work.  They sent me on my way with "well,
it still won't work but at least it will keep you busy for the rest of the
winter".  Oh yea of little faith...  Nothing I like better than proving
somebody else wrong   :)

Pull your old speedo out of the dash and disassemble it.  Once you have the
face of the old speedo out of it's case you'll notice it's a little smaller
than the Verde unit (or 2.5 Milano as needed) Now break out your dremel
tool, file, and knife and start hacking away at the case.  First I removed
the back 1/2" or so of the case so I could access the inside with the speedo
installed.  Then I had to grind away some of the extra protrusions within
the case to make extra clearance for the new speedo.  Despite all this,
you'll soon see that there is no way to get the full face of the new unit in
the old housing, so you'll have to cut away part of the perimeter of the new
unit.  It's not pretty, but on mine I had to cut it down to the point were
on the right side I cut off the '0' of the 120 and 140 mph marks, and about
1/3 of the left most indicator numbers on the other side.  Everything is
still readable, and only 4 of the indicating numbers are compromised.
You'll also have to cut the four corners at 45 degree angles to fit it in.
Go slow here and keep trial fitting the face to the housing until you get it
right.  Remember that it's a lot easier to remove more material than to put
it back later.

I also removed the circuit board from the speedo (it's held on by one screw)
so I could re-position it inside the case.  More on this board later when we
wire the thing up.

Once everything fits, spray the inside of the case with flat black paint and
fit it all together.  Don't glue it up yet, as you still have a little work
to do on the circuit board.   I didn't use the plastic insert trim of the
original speedo so I could gain that extra bit of clearance around the
edges. You will also have to drill a small hole in the clear cover to accept
the new trip-odo reset lever sticking out of the face of the new speedo.

Go down to Radio Shack and get male and female 4-pin connectors.  They're
about a dollar each.  On the edge of the speedo circuit board near the
corner with a notch cut out of it you will see a small 4-pin connector.
Break out your handy soldering iron and remove this connector and solder 4
small wires about 4" long to each of the resulting holes.  Take care not to
jumper anything here if you are not used to this sort of work.  These four
wires will then connect to one side of the connector you just got at Radio
Shack.  Once you've got all this done, make yourself a note as to which
color wire you used for each pin so you don't forget later and assemble the
whole unit in it's case.

The wiring is pretty simple.  Starting at the transaxle, the sending unit
will end in a factory 3 conductor plug.  Run this up through the rubber plug
in the floor of the car and connect it to it's matching plug on the
amplifier.  You will also see 4 wires going through this plug to connect to
the old sending unit and the reverse indicator.  Cut off the old sending
unit as you will not need it for this.  There are two wires going to it from
the wiring harness- one pink, one red and white.  Be careful to get the
correct ones as my car also used a pink wire for one of the reverse
indicator wires.  Now cut of the remaining 3-pin connector on the amp.  It
has a red wire which you want to connect to the pink wire of the old sending
unit harness, and a white wire which gets connected to the red and white
wire of the harness.  The third wire is a shield which you can connect
directly to a chassis ground.

Back up in the dash you will have to cut the old speedo plug away to install
the other half of the 4-pin connector you got from Radio Shack.  You will
find the old plug contains the other end of the pink wire and red/white
wires you were just working with at the speedo amp.  Remember the note you
made about which wires you attached to the speedo circuit board?  Here's
what you want them to attach to in the car-

Starting from the notch in the board the first pin is switched +12v, the
second is ground, the third is the pink wire from the harness, and the
fourth is red/white wire from the harness.  Once you've connected everything
with your 4-pin connector, your ready to go.

What's the downside?

Well, I didn't allow for lighting as yet.  I was in a hurry to finish the
project so I'll address that issue later.  It shouldn't be too hard.  The
other bad part is that you have to cut the edges of the numbers down to fit
the new unit in the old case but it can't be helped.  I suppose you might be
able to use a late GTV6 speedo and make it work, but in my case the gearing
would have been different so the speedo would have been off anyway.  On the
plus side, I now have a cool 160 mph speedo that works...

You can find all this info except for the pin out of the speedo circuit
board at the GTV6 website.  I suggest you take a look there before
attempting this on your own as they have nice pictures and better
descriptions of the procedure.  If anybody has a specific question, I'll be
glad to help.  Just let me know.


Don Happel       zelatore@domain.elided
Shemp Mo-Din Italian Motorsports
"it's good to go very fast"       - Peter Egan

------------------------------