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Looking for a wire that's only live with the ignition on....

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Old Mar 20, 2004 | 11:12 AM
  #1  
pwhite8314's Avatar
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From: Dallas, TX
'09 Audi A5
Looking for a wire that's only live with the ignition on....

(cross post from the W209 forum)

I'm fitting a radar detector, and need a suitable power wire, preferably from the fuse box on the driver's side of the car (fuse #'s 20 -32 (or thereabouts). I've probed each of them, and they all seem to permanently live.

Anyone have a good fuse number i can use? I'd rather go from that fuse box if I can, as it makes my cable run very short (and easy!)

Thanks

Pete
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Old Mar 20, 2004 | 12:10 PM
  #2  
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From: Dallas, TX
'09 Audi A5
Actually, let me ask it a different way, as I think all the wires to that fuse box are always live.

I've mounted the radar detector on the far right of the dash (UK car, so right-hand drive), and it's got a 2 metre power lead to go to the cigar lighter. I'd rather hard-wire it, so I'm after an easily-accessable wire I can tap in to for the 12v. I've got the cable as far as the seat electrics (which is about as far as it'll reach), but they seem to be permanently powered as well.

From it's current position, I can get up as far as the centre light, and down as far as the seat electrics or anywhere behind the dash. From where I've removed the side panel, I can see a wodge of wires going to the headlamp switch assembly, but I've no idea which of the wires is live.

In my old TT is was easy, as some of the fuses were only live whilst the ignition is on, but I'm quickly coming to the conclusion that the CLK is very different

Help!

Thanks, Pete
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Old Mar 20, 2004 | 12:28 PM
  #3  
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From: Silicon valley
Audi C7.5 S6
I think there be a wire running into the radio connection, that is only live, with the ignition on.

I don't know, if this correct for your radio, but, pin 7 of Conn A, would appear to be the correct wire.

http://www.beckerelectronics.com/1492.html

Don
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Old Mar 20, 2004 | 12:41 PM
  #4  
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From: Dallas, TX
'09 Audi A5
Thanks - I've got COMAND fitted; what you say is probably still true, but if at all possible, I'd rather not have to pull it out, as I don't have the special tools. If I could find the other end of that wire in a more convenient place, then that would be great!
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Old Mar 21, 2004 | 03:53 PM
  #5  
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I think the only Special tool you need is a T20 Torx. The rest is just a lot of futsing around with removing the vent assembly, above the radio/command.

You might be able to buy the radio connector, with the color coded wires on it., but it still would be research project to find where the wire comes from. A Mercedes wiring diagram would help a lot.

Don
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Old Mar 21, 2004 | 03:53 PM
  #6  
m444's Avatar
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From: Silicon valley
Audi C7.5 S6
I think the only Special tool you need is a T20 Torx. The rest is just a lot of futzing around with removing the vent assembly, above the radio/command.

You might be able to buy the radio connector, with the color coded wires on it., but it still would be research project to find where the wire comes from. A Mercedes wiring diagram would help a lot.
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Old Mar 22, 2004 | 03:24 AM
  #7  
pwhite8314's Avatar
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From: Dallas, TX
'09 Audi A5
Oh right - I assumed I needed a tool to release the Cmand via the two small holes in each of the top corners, but obviously not.

Anyhow, I got a bit lucky on this one - I took the carpet up on the passenger side to find the carkit that had been installed by someone more professional than me That also needs to know when the ignition is on, so I just tried the wires until I found the right one, and tapped into that.

All now working OK; usually the difficult bit is running the cables, not finding a power source.
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Old Mar 24, 2004 | 09:20 AM
  #8  
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From: Fl
92 500sel/01 320e wag
Cigarette lighter, or glove box light circuit
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Old Mar 24, 2004 | 02:05 PM
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Dericious's Avatar
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CLS63
Just did a sirius install

i have a w211 and the cigarette lighter powers off with the car.

i had to run a wire to the fuse box for a constant so i wouldn't lose my mem. all the time.

hope that helps.
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