Sylvester20007
Posts: 2
Joined: Sat Nov 03, 2018 11:51 am

Constant 12V with ignition off

Hello, all.

First post, I have a Citroen C-zero, so basically an imiev.

I'm trying to install a new stereo, but am having a problem with the memory getting wiped after the ignition turns off. I need a constant 12v to keep the memory charged and then the normal ignition on 12v to bring the radio on once key is in.

I have tested every wire on the quadlock connector with a multimeter, but all are without power until the key is in and turned.

I'm guessing I have to tap the fuesbox for a constant 12v.

Any help would be much appreciated.

Thanks

SyLvEsTeR
kiev
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Joined: Sun May 03, 2015 7:15 am
Location: The Heart o' Dixie
Contact: Website

Re: Constant 12V with ignition off

Here is a link to the 2011 radio wiring diagram, you didn't say the year of your car. There is a 12V line fed from the battery thru a fusible link that has power all the time.

2011 audio wiring
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Sylvester20007
Posts: 2
Joined: Sat Nov 03, 2018 11:51 am

Re: Constant 12V with ignition off

Many thanks for the diagram.

It's a 2012 year.

I'll check and update the thread. Many thanks

SyLvEsTeR
PV1
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Re: Constant 12V with ignition off

There definitely should be a live 12 volt line to the radio in the stock harness, although there is no ground. Typically with the adapter cables, constant power is Yellow and switched power is red. The color code of the stock harness doesn't follow this, though.

When I was messing around with different radios, I had to use a chassis ground. On the US models, just to the right of the radio inside the well, there is a metal piece that runs up to where the radio bolts in. This provides the ground to the factory radio. On my aftermarket radios, I had to run the ground line to the screw holding the bottom of this metal piece in for the radio to work.
"Bear" - 2012 Diamond White Pearl ES with QC
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amar
Posts: 20
Joined: Thu Feb 03, 2022 10:53 am

Re: Constant 12V with ignition off

Hi. I just registered in hope for you guys to help me - I would really appericiate it as we two have the same problem!
I also tested my wires, all showed 0volt when no ignition. Ive tested the cigarette lighter thing, it had 14.4 volt when car was on.

The green wire showed 14.4 volt aswell when using the metal in the inside the dash - however, no reading when tested against the black one.

The red wire showed 8.8 volt when checked against the black wire.

Mod edit: I have a Citroen C-Zero 2011

Again, I would really appericiate your help! :)

Regards
PV1
Site Moderator
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Re: Constant 12V with ignition off

Hopefully someone can chime in. My I-MiEVs are buried in snow and I can’t get to them at the moment to see which wire color is the correct line.

What I do know is that there is definitely a wire feeding constant battery voltage to the radio. The green one sounds like it could be it, but at 14.4 volts that could be ignition voltage. Put the black lead of your meter to the metal strip to get ground, and then check each line in the harness with the key off with the red probe. One of these should read 12.something. That will be your constant power. Be aware that you can’t run anything really power hungry from this or the fuse will blow.
"Bear" - 2012 Diamond White Pearl ES with QC
"Koorz" - 2012 Cool Silver Metallic ES with QC
"Photon" - 2017 Bolt EV LT in Orange with QC
2018 Tesla Model 3, LR AWD, MSM
Solar-powered since 10/10/2013
amar
Posts: 20
Joined: Thu Feb 03, 2022 10:53 am

Re: Constant 12V with ignition off

I will re-test tomorrow - as of todays test with key off, I got 0 voltage on all three wires (red,green,black) when having black probe on the metal and red probe on the wires.

If I confirm this tomorrow (that none of them has constant power) - what would be the next move?

I bought a piggyback fuse today, would it be a solution to tap into something in the fusebox? Green already shows sirca 14.5 volts when ignition on, so maybe replace the red that shows sirca 9.5 volts - with a wire leading to a piggyback fuse in the fusebox?

Also, should I splice the ground wire of the ISO adapter and screw it into the metal bit?
Last edited by amar on Fri Feb 04, 2022 10:41 pm, edited 1 time in total.
amar
Posts: 20
Joined: Thu Feb 03, 2022 10:53 am

Re: Constant 12V with ignition off

PV1 wrote:Hopefully someone can chime in. My I-MiEVs are buried in snow and I can’t get to them at the moment to see which wire color is the correct line.

What I do know is that there is definitely a wire feeding constant battery voltage to the radio. The green one sounds like it could be it, but at 14.4 volts that could be ignition voltage. Put the black lead of your meter to the metal strip to get ground, and then check each line in the harness with the key off with the red probe. One of these should read 12.something. That will be your constant power. Be aware that you can’t run anything really power hungry from this or the fuse will blow.
I can now confirm that there’s no constant power on any wires, voltage on red (9.5volts) and green (14.5volts) only when ignition is on

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