Technical Mk2 stereo unit wiring - advice request

[roger057]

Hi everyone,

First I should make it clear that I have been reading up on this for a few weeks now, and I have read lots of threads on Fiat Forum on this issue :chin:.

I intend to install an aftermarket stereo unit into my 2003 mk2 punto, it's a active sport 1.2 8v. I have the fascia adapter, release keys, and will soon have to aerial adapter also. In addition I purchased a fiat to ISO wiring loom adapter, so that any wiring modifications would be done on that rather than risk damaging the original loom.

Having read about the CAN bus system, I was getting ready to fit a piggyback fuse off the cigarette lighter in the fuse box next to the steering column and then attach to the red switched 12v on the new wiring loom, as per the advice on the forum.

However, looking at the existing wiring it seems to actually have a switched 12v installed already. I mean, the wiring matches exactly with the new wiring loom, which is (helpfully) labelled so I know which should be switched 12v. Is it possible that some puntos came wired with a switched 12v? I have seen photos of wiring that clearly has no 12v switched - there are less wires.

I have included photos of the back of the unit and of the new wiring loom, so you can see that it seems to match exactly! Does anyone know what the four wires in the yellow block above the ISO on the unit are for?

I am going to test the wires to make sure, what would be the result if it is a 12v switched? 0v when off, 12v when ignition on I am assuming. Finally, if I undo the connections at the back of the radio to test, will it ask for a radio code when I reconnect?

Thank you for reading and in advance for advice! Sorry it's so long but just need to make sure as it's auto electrics.

 

[Ziggy122]

Right the ISO connector is made up 2 parts
1 side has 8 wires
These are the 4 speakers +ve and -ve wires for each

Then you have the other side which is power

IF your Cars wiring loom is the same as what shown image no4, bar the orange wire the you by the looks of it have a NON canbus stereo fitted and should be able to plug and play a new stereo with ease

If your unsure, with a Test light or a multi-meter check that
Red is live all the time
and that yellow is ignition controlled
However it might be other way around i cant remember, if so its a plug and play job

Except for the 3 coloured connector which wont go onto a new stereo

Orange wires tend to be only for cars that have a different wire for dash illumination

Ziggy

 

[roger057]

Thanks Ziggy, I have tested the voltage and the original wiring does indeed have a switched 12v feed. It seems a bit odd but I'm not complaining as plug and play will be really easy!

 

[MightyMutley]

i followed this thread, works a treat
https://www.fiatforum.com/punto-gui...n-using-iso-yellow-red-wires-3.html?p=3340693