Ignition Switch Wiring ?
 

Due to a fight for position between my dash and my ignition barrel I’ve instead opted for a dash mounted ignition switch. Easy job I thought ! That was until I lopped off the old wires and found I had one spare wire which I have no idea what it’s needed for. The old ignition switch has 5 wires and as far as I can tell they are:-
+12V
Accessories
Ignition
Start
Earth (or at least this is what my multimeter is telling me)

My new ignition switch has the following:-
2 Pins for +12
Accessories
Ignition
Start

I tried just connecting up +12, Ignition, Accessories, and Start. When I go to start I can hear the relay click but no cranking.
I thought I’d try the old switch again and just not connect the Earth wire – same thing…the relay clicks but no crank. When I connect up the earth wire, she fires into life.
So my first question is what is the earth wire for and where should I connect it :confused: (no smart-ar$e answers please).

My second question is that I wanted to hook up a red starter button. Would I need to run this off the Ignition pin from the switch? I assume the current through this will be OK for starting ? If I connect it to +12V then it would try crank even when the car is off if the button is pushed. Anyone done this already ?

Thanks,
Adrian.

My guess would be; one of your +12 wires is the equivalent to what you are calling the old earth (negative from battery).

The +12 may not be referring to 12 volt positive.
It may mean 12 volt plus (ie:12-14v) pos. & neg.

With the second question.
I'd wire the start button through a relay and then on to the ignition.
That would simulate the turning of the key to start. If the button is not pushed the ignition wouldn't get any power.

Adrian..hope this is of help ..

5 position ignition switch should have:

+ 12v battery feed
Accessories B+
Ignition switched B+
Ignition coil (start/ Run)
Start (to solenoid S terminal)

Your harness however may have 6 wires to the switch:

+12v
Ignition coil (run)
Ignition coil (start)
accessories B+
Ignition switched B+
Start

On some fords the Ignition switch is designed to bypass the ballast resistor during start. The wire supplies power to the coil, bypassing the ballest resistor when the switch is in the "start" position. Once the engine has started and the switch released (run), power is supplied to the coil thru the ballast resistor. If your switch does not support this 6th wire then you can jumper it to the (run) wire.

Re Start button: Depends on the button you're using but normally run a wire from the ignition switch "run" or "on" terminal
and wire it to one of the two terminals on the button.
Run a wire from the other terminal to the starter relay.

Some push button start buttons also have more than the two termainals.. the extra terminals serve the start and run circuits.

Hope this helps

Cheers

Thanks Jas & Les,

I found the circuit diagram for my new ignition switch. See pic attached. It's a bit scrtachy but the two spade connectors in the centre of the switch are both connected together.

The old ignition lock/switch I was using was off a Mitsubishi Colt which uses a 5 wire harness. The ignition wire has a wire spliced to it running off to the ignition coil. Is this what you were talking about Les ?

My new switch has 5 spade connectors but effectively just 4 since the two in the middle are connected internally.

If I connect this spare 5th wire I have on the harness to the second middle pin then I'm afraid it will produce a short. When I checked it on the multimeter, there was 0 ohmns to ground.

Still a bit confused as to where/what this spare wire goes to. Perhaps I'll need to fire it up and drive somewhere to have it checked out.

Cheers,
Adrian.

Hi again adrian,

Sorry mate...but even when I blew up that ignition switch diagrame I couldn't read it.

But ..

It doesn't look much different to my lucas ignition switch. My lucas switch also has 4 terminals but connectors 1, 2, and 4 have 2 blades to each terminal . Pin 3 on mine is a single spade connector.

Pretty easy to sort what is what with a multimeter. disconnect the switch all together or you will be reading down and back circuits. Check continuity from the double center connectors (assuming that is Bat +) to the other terminals.

My switch has 4 positions ie the key moves to 4 positions) and terminal 1 is the batt + connector.

Turning the key fully anticlockwise produces the following:

between terminal 1 & 2 ziltch
between 1 & 3 ziltch
between 1 & 4 woohoo...continuity

turn key to second position I have:

between 1 and any of the others .. Ziltch

turn key to third position I have:

between 1 & 2 continuity
between 1 and 3 nuttin ziltch
between 1 and 4 continuity

turn key to 4 position (spring loaded start) so hold this on:

between 1 & 2 continuity
between 1 and 3 continuity
between 1 and 4 Ziltch nuffin

Sooooo from this lot I can deduce:

position 1 of switch ( fully anticlockwise)
Terninal 4 has continuity...so thats accessories

position 2 of switch:
Nothing has continuity so thats all off

position 3 of switch:
terminal 2 continuity so thats ignition
terminal 4 is on and is accessories same as in switch position1

Position 4 of switch ( ie spring start)
terminal 2 is ignition as before
terminal 3 is start (to starter solenoid)
terminal 4 (accessories) nuffin

so that's it mate.....accessories goes off when starting the car as you dont want a spike to the accessories, but it turns back on when the key returns back to position 3.

Now...all ya gotta do is identify what wires are what in ya harness.

Regarding the solenoid clicking but no start...I think that's prolly a different problem to ya wiring ( like stuck bendix gear maybe)...dunno.

I do have a wiring diagram for the colt if you want it.

Hope this helps
cheers

Thanks Les for that detailed response.

I had another go at it on Saturday and with the additional help of John Cini found that the spare wire was in fact my starter relay wire. Still not sure why I got 0 ohms across it with the multimeter as a relay should provide some resistance.

Anyway, the wire I had connected to the start terminal was in fact a brake fail lamp test which goes through a relay (hence the click I heard). On the old switch this got power momentarily before the starter would kick over. To fix my problem I connected the brake fail lamp test wire to the ignition, the start wire connected to the start terminal and, voila, she fired up.

Also got my red start button working. I did as you suggested Les and took a line from the ignition to the red button switch and the other switch terminal down to the starter relay.

Thanks for your assistance. At least now I should be able to get to the Nats. :)

Cheers,
Adrian.

Adrian,

Wiring issues can be one of the most frustrating issues you can have with your car, but boy when you fix it you wonder what all the drama was.

Well done, and any ignition issues your the man.

I'm pretty good on instrumentation clusters - what wire goes where etc;)

Great stuff Adrian, had to be some thing simple.

Now, can I print your post and show my first wife?. ;)

She claims I know absolutely bu$$er all about pushing buttons.

:LOL: :LOL: