cd wiring

[jond]

hi just fitting a new radio and got a few problems with the wiring fitted to the car from new
there are four wires to fit
first one is permanent live red
then brown earth these 2 work fine
then there is a yellow wire which gets no power not sure what this one is for
the last wire is blue/grey this only gets power if i switch the lights on so i can only use the radio with the lights on
i know the wiring was for an old system but how can i get the radio to work without having to switch the lights on
i dont want to butcher the wiring so any tips or diagrams would be great, thanks

[ianaudia4]

Red is perm live, brown is earth.
The blue and grey cable is there as in the old days radios didn't light up until you put the lights on (your ashtry and fag lighter is on the same loop), you shouldn't need this on a modern head unit.

A yellow cable is usually from the radio, this goes to a perm live so you don't lose the station memory.

Does your car have the original ISO plug? if so you can buy the plugs that would fit straight into your radio, usually from any decent ICE shop.

If someone has wired in a radio they may have taken a switched live.

[jond]

thanks for the explanation the cd wont work without the switched live so to use it i have to connect the blue wire and switch the lights on , to get it to work without the lights i need to find out why the yellow wire has no power with the ignition on or off any ideas where it goes to

[ianaudia4]

Did the head unit come with a handbook? If it did the wiring diagram should tell you what needs to be connected.

Sciroccos came with a permanent live (red) which along with the earth should power a head unit up.

Does the red cable have an inline fuse connected? Is fuse number 3 in the fusebox intact?

[jond]

yes checked the hand book and it needs both permanent and switched live to work the red wire works fine and has constant 12v power, i just need to find out why the yellow wire has no power then it should all work fine cheers

[the edmundator]

On most modern radios there is a way of connecting the switched and permanent live wires together without any cutting, as they have extra branches with plugs on the ends that simply push together.

If your radio doesn't have this, you should be able to buy an ISO loom from Autoleads (or similar) which allows you to do this. Just put this loom in between your radio's wiring and the car's.

If you use your car regularly, this shouldn't cause a problem, but it will drain the battery more quickly if the car is left idle for several weeks. I find any more than a month is a problem, so I disconnect the battery if I don't think I'm going to use my car for a while.

[the edmundator]

The blue/grey wire you mention is probably wired up for radio illumination, hence why it comes on with the lights. If your radio doesn't have an illumination wire (which would dim the display when the lights are on to make it less bright at night), you should just safely isolate this wire and leave it unconnected (or remove it).

The yellow wire needs to take its feed from the red one, as above, or you need to find a source for a switched live feed to wire it up to come on with the ignition.

[jond]

thanks any info on what the yellow wire fitted in the original loom is for could it have been for an electric ariel and that's why it gets no power thanks

[the edmundator]

I don't remember ever seeing a yellow wire as part of VW's loom, so can't really help you there.

[ianaudia4]

No, the electric aerial was a blue wire, standard fit on a MK2 Storm.

Do you have a picture of the wiring, it could have been changed from standard at some stage?

[jond]

i decided to connect the live switched live together as suggested and it work ok for now if i remove the front of the radio when not in use will the radio still drain the battery as for the wiring it had iso blocks fitted and they looked to be original is that right for a 1988 car it has 4 wires red yellow brown blue not sure how to upload photos i will be taking the car to a few vw shows so will see if i can speak to another owner and pherhaps see how the radio is wired in thanks

[fonzooorooo]

The battery'll only drain significantly if the radio's faulty.

I normally wire them all permanent live so I can have the radio on without the keys in (spannering, cleaning, camping etc!)