Technical Best Place To Get a Permanent Live Feed For The Radio

[GettinBetter]

What's the best route, and place to get (as the title says) a permanent live feed for my 3rd party (Xtrons) radio.

Ref: 2013 Fiat 500 twinair lounge.

Asking for a friend me.

I'd prefer not to go through the bulkhead and was hoping there might be a live from the body ECU?

 

[John202020]

Isn't the radio feed permanently live( that's why you can turn it on with the key out) it's a switched feed you need, from the lighter socket?

 

[GettinBetter]

Isn't the radio feed permanently live( that's why you can turn it on with the key out) it's a switched feed you need, from the lighter socket?

Mm, I'd say it's the opposite. The switched feed is just that, it's switched by the ignition key. A (fused) permanent live, still allows me to turn it on when the key is off position.

I'm currently perusing the Body CM circuit diagram, for a spare connection with a sensible sized fuse.....

 

[John202020]

Use a meter to see if the feed wire to the radio is live, it "must" be permanently live as you can open the door and press the on button on the radio and it comes on key in pocket, it's the can bus system that tells the radio to turn on when the cars started, is it not?

 

[GettinBetter]

Use a meter to see if the feed wire to the radio is live, it "must" be permanently live as you can open the door and press the on button on the radio and it comes on key in pocket......

Mine doesn't. When the key is off the radio is dead as a dodo, so is the cigarette lighter socket.

 

[John202020]

Interesting, yes the lighter socket will be dead key out, think it's on the radio, that the radio time out can be set( old Blaupunkt version) 0-20 mins so perhaps if set to zero it won't turn on? But still check what's actually on the feed wire, from memory only 4 wires feed earth 2 can bus plus speakers etc

 

[GettinBetter]

I recently looked through the manual for the radio, and it shows another connection for ACC (accessories, which I never fitted cos I'm a lzy sh-t, and was in a hurry) but the fiat doesn't have such a position.

So I thought I may as well connect it to another permanent live source.

 

[John202020]

Think its a case of pulling the old radio out and testing the voltage on the supply wire that will say once and for all?

 

[jrkitching]

the lighter socket will be dead key out, think it's on the radio, that the radio time out can be set

Yes, auxiliary socket needs key on; radio is live with key out

 

[GettinBetter]

Think its a case of pulling the old radio out and testing the voltage on the supply wire that will say once and for all?

This is an Andriod type 3rd party Xtrons radio, will that make any difference to your theory?

 

[GettinBetter]

.... radio is live with key out

Well you all make a convincing argument, & I would like to get to the bottom of this.

 

[GettinBetter]

Think its a case of pulling the old radio out and testing the voltage on the supply wire that will say once and for all?

Ok, I will.
And it should be live with key off...

 

[jrkitching]

Well you all make a convincing argument, I would like to get to the bottom of this.

All I know for sure is that you can turn the radio on with the key out (with the factory standard radio in an unmodified car).

There's a lot of electronics behind this; it doesn't necessarily mean there's a permanent useable live feed to the radio; there are other ways this function could have been implemented.

 

[GettinBetter]

All I know for sure is that you can turn the radio on with the key out....

Ok, understood.

.....there are other ways this function could have been implemented.

Oh Yes, I agree.... and I can't help thinking the accompanying CAN bus adaptor box may have something to do with it.

 

[John202020]

One other possibility is that the can bus is live, and it's this thats "live" in the radio and its this that then switches the power on? All will be revealed at the testing of the feed wire

 

[jrkitching]

And be careful if experimenting.

There are various ways an accidentally shorted stray live feed in the wrong place can do some expensive damage, as some of us who've experienced the hatch wiring fault can testify.

And if you try to take significant current from a switching feed, that might not turn out well either.

We're not in Kansas anymore.

 

[John202020]

And if you try to take significant current from a switching feed, that might not turn out well either

Certainly so
In the old days the red permanent live provides the main power feed for the power amplifiers in the radio pulling easily 10a, the yellow switched feed only tells the radio to turn on that's why sometimes the red is far thicker similar to the black earth wire, if you use the lighter socket as a switched feed there's no issue, especially as it won't carry much power at all it's the main power feed you need to check especially if it's a high power unit and like me push my 350w rms system( about 40A ) to the max?

 

[GettinBetter]

One other possibility is that the can bus is live, and it's this thats "live" in the radio and its this that then switches the power on? All will be revealed at the testing of the feed wire

I think you may be closer to the answer than you think here, but we'll see.

..and don't worry about loadings, I'm well versed in that area.

Thanks for your input guys, you given me a few points to think about whilst exploring.

 

[John202020]

I think you may be closer to the answer than you think here, but we'll see.

..and don't worry about loadings, I'm well versed in that area.

Thanks for your input guys, you given me a few points to think about whilst exploring.

Let us know what you find out would help all of us in the future?