Digital Cluster

[Jim Gathmann <jim_gathmann@xxxxxxxxx>]

Subject:
Ever wanted a digital dash in your analog
Dynasty/Imperial/etc?

Summary:
I did it (I think)!

Installed a digital dash in my (what was analog
cluster) AC/AY.

Man. What a job that was. Started friday at around 5
pm, and I'm just now about finished (and did 2
all-nighters with only 4 hours of sleep, lol).

It appears to be a possible swap without exchanging
body computers, etc.

TEXT:
Basically I took my FSM, looked at how the analog
cluster wires up, and how the digital cluster wires
up. I noticed that several of the digital wiring
(about 8 or 9 of the 13 wires going to the digital
cluster) are the same as some of the wires going to
the analog cluster. Some analog cluster wires are not
used by the digital dash...

I then figured out what the remaining 3-4 wires were,
and how to tie them into the car's electrical system.

I then remved my dash trim, analog cluster, battery
cables, etc.

I cut off the old analog cluster connector harnessesd
(2), while leaving about 1.5" of wire still attached
to the old connectors. Lacking the connector which
plugs into my digital dash, I took the cluster apart,
and used a sodering iron to remove the pins on the
back of the cluster. I then directly sodered wires to
the PCB.

Then I spiced into the analog cluster's wiring as
needed, and ran two wires for the CCD (computer code
transfere buss for these cars- basically it goes to
the diagnostic port and the diag readers use the CCD
to collect info on the car- the digital dash
translates this code and uses it to know what to
display on the gauges), a few other odd-ball wires,
etc and put the cluster in. To get the +12 volt inputs
for the cluster, I went and taped into the radio fuse.

Turned the key, blew my 40 amp rade fuse.... no one
sells fuses in 2 AM sat night (dope!). So I ran off of
a different fuse for testing my connections.

Turned the ignition switch on- dash light up, worked,
idiot lights all worked, turning on the headlights
dimmed the backlite gauges... all good thus far.

Volt meter, fuel level, odometer all worked- couldn't
check speedo, temp, oil psi without running the
engine...  turned on the engine- temp and oil worked
(didn't drive the car- so speedo not checked yet-
couldn't drive with no dash, and soooo many wires all
over the place that I couldn't GET to the gas pedal!).

So all apeared good and done. Well- kina. One glitch.
There is an electric buzzer under or in the dash
somewhere on the passenger's side. When you leave your
lights on, doors open, keys in, etc., you get that
buzzer going off. Well, for some reason, with the
cluster in and working, I get a constant buzzer sound
(that high pitched, ear piercing siren). Ok, so I
could play the radio so I don't hear it- BUT, the
buzzer stays on EVEN when the ignition switch is in
the off position (??).

Looked over the FSM- the body computer uses fuse 8 in
several circuits- some of the idiot lights, the car
message centre (picture of a car by the headlight
switch- when a door is open a red LED lights on the
picture...), and a few other things (including the
cluster). With 8 inplace, I get the buzzer- with 8
removed, no buzzer- so I went to find the buzzer so I
could just pull it (and then everything would work,
and no sound and electric draw when car is off). WHERE
is the buzzer? Spent some 12 hours taking off parts of
the dash, felling around- could not find it. Checked
all 4 fuse/relay boxes (yes the AC/AY's have 4- two of
which you can get to without removing the dash!).

So I'm slowly re-wiring each circuit so it doesn't use
fuse 8-- one circuit at a time. Once I hear the
buzzer- I know which circuit is the problem.

So far, I've re-wired the cluster so it uses a
different fuse, most of the idiot lights.

Next to do are the rest of the idiot lights and the
message center (<-Which is what I suspect is the
problem). So I called it quits until next weekend- put
the car back together, cluster in and appears to be
working. Tomorrow I see if the speedo works when I
drive to work...

Looking back, I would have gotten the other end of the
cluster's harness so I wouldn't have to take apart the
unit and re-wire the PCB! I wouldn't advise this
upgrade unless you all have the FSM handy, already
know how your dash is pretty much wired, AND are very
fimilar with electronics.... this was not easy for me
(took almost 3 days and 2 nights) and I can build just
about anything with electronics....

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