2003 Punto head unit issues.

[phaserrifle]

Thinking it would be an easy job, I removed the blauplunkt tape player from my punto, to replace it with the pioneer DEH-2220ub head unit that I took from my old fiesta.

I plugged in the new head unit, and nothing happens. doesn't matter what position the key is in, the unit won't switch on.
I tried googling the issue, and asked at my local car audio shop. they suggested splicing the red and yellow wires (switched and constant power) together. I've tried this, but it didn't seem to have any effect.
I've also tried to plug the original head unit back in (to check I've not blown a fuse or something) and that doesn't do anything either. But the fuses all check out fine.

At this point, I'm hoping someone can help with any ideas as to what is going on.

 

[PuntoHowTo]

There is extensive information on this on the forum but basically you need to buy an adaptor cable which isolates the digital connections from the cars computers to its standard radio, not doing so can cause serious damage to the cars electrical systems, sometimes resulting in the need for a new body computer at £300
On the punto these digital connections are on the ISO wires usually reserved for the power on a normal ISO plug

If your local car audio shop doesn't know this then I strongly suggest you never go back to them.

 

[phaserrifle]

There is extensive information on this on the forum but basically you need to buy an adaptor cable which isolates the digital connections from the cars computers to its standard radio, not doing so can cause serious damage to the cars electrical systems, sometimes resulting in the need for a new body computer at £300
On the punto these digital connections are on the ISO wires usually reserved for the power on a normal ISO plug

If your local car audio shop doesn't know this then I strongly suggest you never go back to them.

Am I right in thinking the Autoleads PC2-36-4 is the cable I need?

And if I've screwed up my electronics, how would I know?

 

[phaserrifle]

Ah! a friend has dug out an old adapter he thinks is for the punto (he had one a few years back)

It has two connectors. the first one is labelled up for the speakers. has all the pins used, straight through.
The second, with labels for power etc has pins and cables on pins 4 to 8 on this diagram: (male side), these also are wired straight through (so pins 4-8 would be used on whatever the female side get's plugged into)

Is this the cable I'm looking for? I will have to split the plug in the car, but that looks to be a couple of seconds with a knife or hacksaw, just to cut the connecting plastic between the two plug halves.