What are these two plugs for?

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toby
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Thu Mar 19, 2009 5:10 pm

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These two plugs next to the ECU - what are they for?

I've tapped into one for a lights-on warning buzzer but I don't know if this is a good idea now as I'm not sure what this green wire on one of the plugs is really for. It's a handy connection as it goes to earth with the ignition off, with the buzzer connected to the dash light live, it buzzes.

Maybe there is a better wire for this warning buzzer?

Thanks for any advice.
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Brianmoooore
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Thu Mar 19, 2009 6:18 pm

The only uses I've seen for those plugs are for air con and switchable auto gearboxes.
If the wire is plain green, then it's unfused ignition live.
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jay528ise1985
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Thu Mar 19, 2009 6:22 pm

One of the connectors has a pin for idle speed increase with air con on (I've used this pin to increase idle when my cooling fan is on high speed), and one of them is for auto cars to raise or lower the idle whilst engaging or disengaging gear.

I think the connection you mention is something to do with fuel pump as I used it for a phantom warning light that lit up when fuel pump stopped.
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toby
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Thu Mar 19, 2009 6:41 pm

Thanks for the replies.

It's a green wire with a purple stripe.

As long as it isn't an input to the ECU - which is what I'm worried about.
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Brianmoooore
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Sat Mar 21, 2009 10:36 am

The green/purple you have connected to is the wire that goes from the fuel pump relay to fuse 11.
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stu79uk
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how do you know all this brian mispent youth I think LOL
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toby
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Thu Mar 26, 2009 4:16 pm

So this wire is live when the ignition is on and an earth when the ignition is off.

I've added a 5amp fuse to where I tapped into this wire.

Should be OK right?

Cheers
Toby
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Brianmoooore
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Thu Mar 26, 2009 4:42 pm

toby wrote:So this wire is live when the ignition is on and an earth when the ignition is off.

I've added a 5amp fuse to where I tapped into this wire.

Should be OK right?

Cheers
Toby
Wire will be live with the engine running, rather than ignition on, and will be connected to earth via a resistance of a few ohms (fuel pump motor winding), when the engine is stopped.
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toby
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Thu Mar 26, 2009 4:47 pm

Wire is live with just ignition on according to my testlight.
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Brianmoooore
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Thu Mar 26, 2009 7:24 pm

In that case, it's not the fuel pump wire! (Unless someone's been playing with your pump wiring.)
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