If you have the base model, it’s very likely that
your car is missing bits and pieces. Things like oil pressure and volt gauges, a
trip computer, climate control, cruise, electric windows and electric seats. Ah,
you think, that’s easy enough to solve – just visit a wrecker and pick up these
good bits. Trouble is, what you see is sometimes only the tip of the iceberg –
getting the system working might require a lot more than just the stuff on the
dashboard.
What’s easy to add and what’s hard to add depends
a lot on the car. For example, on one car that uses electronic throttle (an
NHW11 Toyota Prius), adding cruise control is as easy as buying the factory
cruise control stalk, buying a new brake light switch, and installing both.
That’s pretty well it – the cruise control light is already built into the dash,
the wiring loom is mostly already there, and the ECU logic is all built in,
ready to be accessed. For just a few hours of time, it doesn’t get much easier
than that.
But installing factory cruise on another car (a VS
Holden Commodore) is much harder. In some trim levels the loom isn’t present, so
that part of the system needs to be bought. Then you’ll need to add the throttle
actuator, control stalk and additional brake light switch. Budget on spending a
full day....
Factory dashboards that have extra instruments are
another case. A dash that integrates a voltmeter and oil pressure gauge into the
display sounds pretty easy to fit – just swap-in the whole instrument panel. And
the voltmeter part won’t cause any problems – the panel already gets a battery
voltage feed and so the new voltmeter will just monitor this. But changing from
a dash that uses an oil pressure idiot light to one with an oil pressure gauge
will require a new engine sender, as the signal output is no longer just on/off
but variable. That’s no big deal, but it is something to be aware of.
And it might look easy to pull out the original
heater/ventilation controls and replace them with digital climate control. In
most cases the panels are physically the same size and the climate control panel
might set you back only $40. But stop! A climate control system uses output
actuators to vary the position of heater valves and ventilation flaps, it uses
external sensors that include sun, outside temp and cabin temp. It also has its
own Electronic Control Unit. Basically, the control panel is perhaps only 25 per
cent of the system. And installing the other 75 per cent is likely to be a
complete dashboard-out job!
Information
What you need to do before you spend a dime is to
get information. Is the upgrade you’re considering possible, and what
exactly needs to be done to achieve it?
In these sorts of the swaps, Web discussion groups
are really useful: if yours is an older car, chances are that someone before you
has tried to do the same upgrade. So pose the question: what else needs to be
done to swap in the instrument panel that contains the oil pressure and volt
gauges? Or, has anyone fitted the upmarket model’s cruise control? Don’t
necessarily rely 100 per cent on the answers, but take them as generically
valid. So if someone says that the upgrade instrument panel swap has been done
heaps of times, you know it’s possible. But that answer doesn’t tell you all the
bits that you might need...
Another excellent resource to use is the workshop
manual for the car. For example, the wiring diagrams of the base and upper trim
models will show you some of the differences in instrument panels, climate
control and cruise. The manuals might even have two clearly different wiring
diagrams: those for the lower trim models and those for the upper trim models.
If the upper trim model runs a different body computer, instrument panel and
trip computer – and they’re all linked together – it’s obviously going to be a
lot harder than if the basics are all the same and the good bits all just plug
into the same system. Factory workshop manuals can often be accessed at larger
libraries and at the libraries of colleges that teach automotives.
Finally, a wrecking yard can tell you lots of
stories. For example, if there’s the top-line model (complete with all the good
bits you want) and right next door there’s the base model you own, and both have
their dashes out, bumpers off and door-trims removed, you can quickly and easy
compare wiring looms. Is it the case that both cars have the same looms, but in
the base model the plugs are just unused? If so, you’re laughing. Or are the two
looms completely different? If so, well, maybe you’re not laughing... If you want
to install the topline model’s foglights and foglight switch, are there wires
running to the front and back of the car for the lights? A quick comparison of
the two cars will soon show you.
Doing It
Any electrics upgrade will be specific to the make
and model of car, so let’s take a look at one. The addition is of the Fairmont
trip computer to an EF Falcon Futura, which normally fills the same space with a
clock. In this case, the trip computer was purchased on eBay complete with the
trip computer wiring plug, a new female plug connection, and specific
instructions on how to do the swap. As a result, the acquisition was more
expensive than buying the trip computer from a wrecker, but the seller also
guaranteed success.... (But see footnote at end of article.)
Here’s the standard Futura clock.
With the dash trim removed, the clock simply
unclips, with the trip computer able to be pushed straight into the same
space.
But the tricky bit is the wring. The trip computer
gets its information (fuel remaining, speed, injector opening percentages) via a
single wire data feed from the dashboard. To gain this info, a new terminal
needs to be inserted into the right-hand instrument cluster connector, seen
here.
This new female pin goes into the connector in
this terminal position.
This pin is then connected to a new wire that goes
to the trip computer connector.
The clock connector can be used for the trip
computer, so long as you add some extra pins. However, it’s easier to take the
trip computer plug and a short length of loom from the donor car. In this case,
in addition to the pin for the dashboard connector being supplied, the trip
computer plug was also supplied. The changeover is as follows:
Pin no |
Pin Function |
Clock Connector |
Trip Computer Connector |
Action When Fitting Trip Computer |
1 |
Trip computer data signal |
No connection |
Blue |
New wire to instrument cluster plug |
2 |
Clock ignition power |
Red/dark green |
Not connected |
Cut wire |
3 |
Battery positive |
Yellow/black |
Yellow/black |
No change |
4 |
Earth |
Black |
Black |
No change |
5 |
LCD dimmer signal |
White |
Black/white |
No change |
6 |
Trip computer buttons light |
No connection |
Brown |
Connect to brown wire on rear demister switch connector |
7 |
Dash lights dimmer signal |
No connection |
Dark blue/red |
Connect to dark blue/red wire on rear demister switch connector |
8 |
None |
No connection |
No connection |
No change |
With the pin numbers being as follows, with the
plug viewed from the rear with the plastic spring clip on the left:
As indicated in the table above, the brown and
dark blue/red wires from the trip computer plug need to tap into the like colour
wires on the adjacent rear demister switch. The two rear demister switch wires
to access can be seen here.
The wired-in trip computer plug can be seen on the
left with the rear demister switch plug at right.
The trip computer temporarily plugged in to make
sure everything is working...
...and then working with the dash put back together.
Conclusion
It’s very important that you thoroughly sort out
the implications of doing the upgrade before you shell out the cash. Yes, it
might be a 1-hour job (as it was with the trip computer upgrade) but
alternatively, it might be a full 2-day job with the dashboard and steering
column needing to come right out of the car (as I understand a climate control
upgrade on the same EF Falcon involves!).
Footnote:
The eBay seller’s instructions for the EF Falcon trip computer upgrade were
sourced from http://www.fordmods.com/forums/doc_menu.php.
For any Falcon owner this is an excellent resource of tech tips on swaps and
upgrades.
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