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Discussion Starter #1
I have a blue flashing LED scanner thingy which i was thinking of fitting to either the dash or roof panel as a deterant as the dark nights are closing in.
Does anyone know of an easy place to tie in for an earth and live (live to activate when ignition is switched off)?
Does the cigar lighter stay live when the ign is off?

cheers
 

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A.O.N. - Platinum Member
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The lighter does stay live buddy,
You should be able to tap into both the + and - behind it, but you will need to rig in a switch to turn it on and off
 

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best way to do it is wire the scanner to the back of your stereo. There will be a constant live, and an ignition switched live there. Wire the +ve scanner to the constant live, and the -ve to the ignition switched live.

That way, when the ignition is on, the LED won't work, but will start as soon as the ignition is switched off. I have done this on several cars in the past and it works fine, no damage to stereo or led.
 

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best way to do it is wire the scanner to the back of your stereo. There will be a constant live, and an ignition switched live there. Wire the +ve scanner to the constant live, and the -ve to the ignition switched live.

That way, when the ignition is on, the LED won't work, but will start as soon as the ignition is switched off. I have done this on several cars in the past and it works fine, no damage to stereo or led.
Am i reading this right? You want to use the ignition live as return for the 12v constant?! Im not sure im totally correct, but I would certainly not be trying that on my car. No offense intended though (Y)
 

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Discussion Starter #6
Thanks for the help, i'll get a switch and use the lighter wires :)

can i get to them from under the plastic under the handbrake or do i have to remove the gearlever surround?
 

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A.O.N. - Platinum Member
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you should be able to pop out the lighter and coin pocket with a flat head screwdriver. But be carefull you dont scratch the plastic
 

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Am i reading this right? You want to use the ignition live as return for the 12v constant?! Im not sure im totally correct, but I would certainly not be trying that on my car. No offense intended though (Y)
None taken, believe it or not it works fine, due to the basic principle of a diode. Put two lives to a diode, and no current can flow at all, which obviously dosen't damage anything. Think of it like a one way door, 10 people pushing the right way through it, but 10 people pushing the wrong way too. Everyone stands still, everyone else goes a different way coz there's 20 people leaning on a door.

Simples.
 

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Lol I do have an A level in electronics, I just havent touched it in the best part of 5 years :)

I dont think I explained myself properly there though. What I was meaning to say was that when the ignitions off the 12v from the constant live is going to be flowing "backwards" down the switched live. I have no idea where the ignition feed goes too though. I think personally thats not a good thing!

As for the diode part, I think your answer is a bit misleading, diodes will only allow flow in one direction - thats the basic principle. Not that your forcing current in both directions to stop it.

Again no offense but I think this is a very bad idea!
 
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