Electric Upgrades

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:

1	5
2	6
3	7
4	8

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.