HU Replacement - Wiring Confirmation Needed

[Batmanan 0]

I went to change the head unit in my Rado and I had a nice surprise I found in the back of the ISO connector from the car there was only 2 wires connected!!

 

The unit I am putting in a an old Sony CDX-M800. The only 2 wires conneted was the HU YELLOW constant +12v wire connected to a BROWN/RED wire and then HU BLACK -ve wire to a BROWN wire. The original HU only comes on with the ignition. I also noticed that on the HU ISO connector the Yellow constant and the Red Ignition wire are together.

 

So from looking around I have come up with what I think the correct colours should be on the car I would just like confirmation of this;

 

RED/WHITE - Constant +12v

BROWN/RED - Ignition +12v

BROWN - Ground -ve

GREY/BLUE - Illumination (what is this for?)

 

Does that seem correct?

[V-Dubstar 0]

The illumination is for the light dimming if the HU has it available - ie when u put the lights on in the car, the HU display should dim slightly.

 

Sounds like u got it right there mate, have u got a multimeter to check the constant and switched +ve?

[Batmanan 0]

I do have one but haven't done that yet just wanted to make sure I had the colours right first.

[smee 0]

You've got them right, according to the Corrado manual:

 

Red - Permanent live

Brown - Ground/negative

Brown/Red - Switched live (ignition)

Grey/Blue - Instrument panel lighting

Blue/White - Speed signal for automatic volume adjustment

 

Don't connnect the blue/white one to anything or allow it to short to the body as it'll stop the spoiler working.

 

Did the old HU lose it's radio stations when you turned off the ignition? Oh and beware if the original ISO connector is still there, VW swap the live and switched live over from the ISO standard. :roll:

[Batmanan 0]

Ok just popped out with the multimeter and my fears were confirmed, there is no power at the RED/WHITE wire but i do get 12v with the ignition on the BROWN/RED Wire.

 

Am I supposed to trace this wire to the engine bay? Is this easy?

 

SMEE - On the original HU I do lose all my stations when I turn off the engine.

[smee 0]

Ok just popped out with the multimeter and my fears were confirmed, there is no power at the RED/WHITE wire but i do get 12v with the ignition on the BROWN/RED Wire.

 

Am I supposed to trace this wire to the engine bay? Is this easy?

 

SMEE - On the original HU I do lose all my stations when I turn off the engine.

 

Thought so, the old HU was just running off the ignition live, so there's no power to keep the memory going when the ignition's off...

 

Have you checked the fuse (no.22 on the fuse box IIRC) for the radio? If you have to trace it the red/white wire should go to the fuse box.

[Batmanan 0]

SMEE - AHA that was it, well its blown at least. The fuse was rated at 20A is that correct as its the only fuse i dont have?

 

Still my worry is why didn't the previous owner just replace the fuse opposed to bodging the wiring.

[Batmanan 0]

I have just seen on a G60 fusebox diagram that it should be 10a, I'm guessing there shouldn't be any difference.

[smee 0]

10A should be fine. The scope for previous owners bodging knows no bounds, on my old G60 I think the previous owner had cut the wire for the front fogs at the switch rather than find out why the fuse kept going...