I have been planning to add a CD player to my car, currently there is no shelf, radio, aerial or speakers. But there is evidence that a stereo did once exist.

The wiring side is where I need your kind help. Behind the ignition switch are the standard 3 wires. Two of which have been tapped into via scotchblock. Could any one tell me what these two wires are for, earth, live etc? And ultimately, what wire on the back of the head unit will each one need to connect to?

One is constantly live into the switch, one is to the ignition circuit from the switch, the other does the starter.

Using a test lamp or multimeter will determine which (or somebody that can remember will be along soon).

Depending how your stereo is meant to be wired, you'll probably have a constant live feed to keep the time, last track and audio settings and a switched live feed which triggers it to come on. When I've done it before I've taken that switched live feed from the ignition circuit and the constant live through a fused wire to the battery.

Disclaimer:

I hate electrics and anything electrical, and everything I've just told you will probably be shot down in flames by somebody who knows better.

Works for me Russell

Well you know more than I do about electrics and I appreciate your help. I am a bit of an electrophobe and should probably leave this to a professional. But that's not the spirit, I want to learn and I'm sure it must be fairly easy.

i personally wired mine straight into the battery. i went through the hole in the bulkhead where the rear loom goes through to go to back of the car... you only need to pass one wire through there as you can earth it this side of bulkhead..
make sure you fuse it just incase though

Eastbourne, do you have a test meter or some other way of determining if a wire is 'live'?

I'd normally be tempted to go through the bulkhead and tap off a fuse too, but, since you already have Scotchblocks on there, it probably makes more sense to stay on this side of the bulkhead and use them! You'll also need a good earth, of course.

As Russsell says, you'll likely need both a permanently live feed AND a switched feed for your CD - you should find both at the ignition switch.

Absolutely fit in-line fuses in both lines. Your CD unit may well have a fuse plugged in to its back - have a look. However, I'm usually only happy when the actual wire itself is protected too, and this means a fuse located as close to the ignition switch as possible.

I don't know what sort of stereo you've got in mind, but my bog-standard one claims to have an output of 140W, so I wouldn't be at all happy using a scotchlock for the feed! It's not much more work to go through the bulkhead and take fused wire straight from the battery. I *think* the switched live feed is really just used as a signal, so you should be OK to use the scotchlock that's there for that, I suppose. I just have mine live permanently, so I can listen to the radio with the engine stopped. Some stereos will tend to flatten the battery if you do that though.

theres a million ways to do it,

my stereo doesnt flatten the battery, can have it go for about 3 hours non stop before and its been fine

DA still yet to permantly fit that speaker system

i used some 30 amp wire straight to the back of the cd player, cut out any switches, ignitions, life is simpler like that, otherwise you have to have the car running to listen to music which can be annoying if our waiting for someone at a train station, (or sit there with the ignition on and cook the coil) but thats my preference to be honest! i tend to use 30 amp wire on everything (mainly because i have a nice big reel of it, which was a gift from a friend!!

A very good point, James, that I'd completely overlooked.

Yes, if your ignition key doesn't have an accessories position, then having to put the ignition full 'on' without the engine running is generally not a good idea at all.

I do have a multimeter, but if I'm really honest, not that sure/confident of how to use it

I noticed the head unit does have a green blade style fuse in the back.
Perhaps an in-line fuse straight from the battery is best. But as I'm clueless about electrics was hoping that I could tap into those scotch blocks.