Basic Circuit info and diagrams.

Post queries regarding your Mk3 Cavalier's ICE and electrical components (head units, wiring, retro-fit toys, upgrades etc.) here

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Basic Circuit info and diagrams.

Post by Robsey »

I regularly get asked for wiring diagrams and wiring info.

However - any queries, suggestions and corrections can be made in this discussion thread.

viewtopic.php?f=15&t=14654

I must point out that I am not an auto electrician, nor am I an electrician of any kind.
My last electronics training was in 2004/5 doing my Electrical Engineering HNC.

What I am trying to say, is that these are my basic ramblings - I AM NOT AN EXPERT!!

First Basic Cavalier Switch Format.

These are wired / configured in 3 ways as follows: -
switch formats.JPG
The main panel switches are listed below, along with their pin / wiring designations.
(For those who want to utilise a panel switch for a different function such as fan over ride or additional lights etc ).
SWITCH WIRES.JPG
Update - Here is the pin layout for the 5 main types of panel switch.
The coloured blocks represent the colour of the switch base insert.

Image

Now then, most project circuits require a relay somewhere along the way due to current levels.

Here are three basic relay styles.
relay types.JPG
It goes without saying, but all power feeds to the relay should be fused - nothing worse than a car fire due to crap wiring. I speak from experience in my early days, where my whole dash set fire in my first car because I wired up an Ammeter with no fuse protection and insufficient wire size.

I will dig out my wiring sizing to suit current draw information in due course.
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Re: Basic Circuit info and diagrams.

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First Wiring Diagram per multiple requests...

Fan Over-Ride, and then an Auxilliary Fan.
Fan Over-ride simply means using a relay to short out the thermo-switch pins.
This means you can set the fan going anytime you have the ignition on, or as a fail-safe if you feel the thermos switch has failed.
BASIC SHORT.JPG
The next two wiring diagrams are for adding an auxilliary fan, although this could really be for adding any accessory, such as auxilliary lights etc.

The main difference between the two, is how the tell-tale works.

The first version only illuminates the tell-tale if the load (horn / lights/ fan) is actually being fed power.
If the relay fails, then the neither the tell-tale nor the load will work.
FAN SWITCH 1.JPG
The second version mimics a standard 4 pin switch circuit and shows the tell tale whenever the switch is closed.
So although a 5 pin switch is shown, you could use a 4 pin switch in this circuit - just ignore pin 5.

FAN SWITCH 2.JPG
more circuits to follow as I pull them from my archive..
Hope it helps someone. :)
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Re: Basic Circuit info and diagrams.

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More Fan Over-ride Circuits.

Standard 1 stage (2 pin thermo switch)
2 PIN FAN PLUG.JPG
2 Stage (3 Pin thermo switch) as used with air-con or diesels.
3 PIN FAN PLUG.JPG
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Re: Basic Circuit info and diagrams.

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Lighting Circuits

Firstly - If you suffer from poor light output, there could be a couple of reasons.
One is the general degradation of bulbs, connectors and wiring, dirtying of lenses and reflectors due to the aging of the car.
Another is the voltage drop caused by the distance covered by the voltage between the battery to the bulbs.
(Via the fuse box, floor connector, switch and out through the bulkhead to the lamp assemblies).

One way to improve this is to use the lighting wires to trigger a relay.
The relay will then link a direct supply voltage from the battery via a fuse directly to the headlamp assembly.

Here is a whole range of circuits to achieve this.
You can make this as complicated as you choose - A person with O.C.D. might fit a relay for each dipped headlight and each main beam, therefore 4 relays in all.
For some this will be overkill or simply too much to comprehend.

So here goes.
Version 1
adapter loom.JPG
Version 2
conv loom 2.JPG
A circuit for both head-lamps
TWIN LIGHT RELAY.JPG

And now for Auxilliary Driving lamps or Fog lamps.
The principle is the same as the image above, but here is the arrangement for a fog lamp / driving lamp circuit using 1 relay.
LIGHT RELAY1.JPG
And another circuit that I found on the web... the wire thicknesses are way over the top, but you get the idea.
driving lights.jpg
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Re: Basic Circuit info and diagrams.

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Making sense of Indicator Flasher Units.

Most vehicles use the DIN system (which is something to do with German motoring standards), commonly adopted by most European manufacturers.

However if you have a different make or a very old model, then some of the flasher unit markings may not make sense... well hopefully this will give a little more meaning to alternative markings.
flasher1.JPG
and
flasher2.JPG
Do note that on some vehicles, especially very early stuff and motorbikes, that some flasher units are round and not the usual square format.
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Re: Basic Circuit info and diagrams.

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Oh yes - current carrying capacity for wire sizes..
CSA = Cross Sectional Area of the wire cores.

These ratings are for wires that are enclosed or under insulation.
Ratings are reduced due to inability of heat to escape.

1mm CSA = approx 11 amps

1.5mm CSA = approx 14 amps

2.5mm CSA = approx 18.5 amps

4.0mm CSA = approx 25 amps

6.0mm CSA = approx 32 amps

10mm CSA = approx 43 amps.

Ratings are increased where cables are able to cool in the air etc...
Ratings in this situation are as follows: -

1mm CSA = approx 15 amps

1.5mm CSA = approx 19.5 amps

2.5mm CSA = approx 27 amps

4.0mm CSA = approx 36 amps

6.0mm CSA = approx 46 amps

10mm CSA = approx 63 amps.

If in any doubt - err on the side of caution, and use the lower values in the first list.
Bearing in mind that cables are under carpets, trims or are bundled together.
Therefore causing problems with heat dissipation.
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Re: Basic Circuit info and diagrams.

Post by Robsey »

Another very common electrical query

Calibra Volt / Oil Pressure Gauges.

Here is the picture for those who are just wondering.
cal gauges.JPG
cal gauges.JPG (25.02 KiB) Viewed 3216 times
If you are struggling to get a sender, then it is recommended that you should short the oil sender pin to earth for the time being.
This will set the gauge to zero.

Leaving the pin disconnected will cause the needle to go to full deflection, which could damage the gauge.

Regarding Illumination -
Grey / Green from the cig lighter will give full brightness all the time the lights are on.

If you use grey / black from the clock or dual info display etc, then this is a dimmer controlled light source.
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Re: Basic Circuit info and diagrams.

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Really basic wiring Colour info

Earth or Ground = Brown

Ignition Live = Black

Permanent Live = Red

Illumination = Grey / Green or Grey / Yellow for full brightness illumination.
And Grey / Black for dimmer controlled illumination.

Aerial Power from the radio = White / Red or Grey / Red.

Calculated Road Speed Signal = Blue / Red

Standard ECU Diagnostic Wire = Brown / White

Dipped Headlamp Beam = Yellow

Main Headlamp Beam = White
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Re: Basic Circuit info and diagrams.

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Dimming Led Circuit -
Wording and schematics taken from pcb heaven.

To make it more easy, i will break the circuit in two parts. The first part will be the controller, which is exactly the same no matter what power supply is used.
The other part is the LEDs.

So, here is the controller:
ledoffdelay_1282208333.png
ledoffdelay_1282208333.png (3.21 KiB) Viewed 3195 times
The R1 protects the capacitor from over-current shock, when the pushbutton is pressed. R2 and R3 will determine the time that the transistor will supply current to the LEDs, as they actually determine the discharge of the capacitor. You should be very careful with the connector "LEDS", because the transistor is NOT protected from over-current. If this connector is grounded for any reason without a limiting resistor, then the transistor will wave bye bye immediately. The LEDs are connected to this connector. According to the power supply and the LEDs that you want to light, you should choose the connection from the bellow suggestions. Note that these schematics applies to LEDs with operation current 30 mA and voltage drop 3.6 Volts! In case you have different LEDs, you need to calculate the protective resistor yourself (go to the LED Resistor Calculator)


To adjust the off-delay time, play with the R3 potentiometer. Higher resistance means more time to turn the LEDs off. You can further increase the off-delay time, by changing the C1 capacitor. You can use for example a 220uF or a 470 uF, or bigger. The more the capacitance, the more the off-delay. Just keep in mind that if you plan to use the circuit at 15Volts power supply, do not use a 16V capacitor. Use a 25Volts or bigger.

Moreover, if you plan to push the circuit to the limits, I suggest that you measure one row of LEDs to see how much current flows, and check if this is the same (or very close) value as i have measure in my circuit. This is because there may be big differences due to the different LEDs that you may use.


To save space, in every schematic that will follow, i will mark the first row with the letter RP for the protective resistor and LED (LED1, LED2...) for the LEDs. This row can be multiplied a number of times, according to the current that is drawn. I will mark the 2nd row with RPN for the protective resistor and LEDN (LEDN1, LEDN2...) for the LEDs, but this line can be multiplied more times.

When powering with 5 volts, only one LED can exist in each row, as each LED drops 3.6 volts. The protective resistor for each row must be 47 Ohms. Each row draws about 24mA. The 2N2222 can handle up to 800 mA IC. So, with 5V power supply you can control up to 33 rows of LEDs, which means that you can control up to 33 LEDs.

With 12V power supply (or 13.4 from the car), each row can have 3 LEDs. The limiting resistor for each row is 47 Ohms, and a current of 30 mA is drawn. This means that the transistor can supply 26 lines of LEDs. So with 12V power supply, the circuit can control 78 LEDs.
ledoffdelay_1282211658.png
ledoffdelay_1282211658.png (2.65 KiB) Viewed 3195 times
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