Q on basic wiring for head unit

[notsofast]

Hi all. The E30 I bought recently comes with a fairly basic JVC radio/CD player. The unit isn't working properly 'cos it can't save any pre-set (stations, clock etc.) in it's memory - all settings are wiped after switching off the ignition. Something wrong with the wiring, I thought.

When I took the unit out yesterday, I found that both power wires (yellow and red) were connected to the car's switched power supply (purple wire). I reconnected the yellow wire from the unit (memory) to what I thought was the car's permanent power supply (red and grey wire) - but the unit wouldn't start up - dead as a dodo!

What am I doing wrong?

BTW, I'm an absolute newbie with wiring up car sterero. I just read this excellent article in the Archive by Paul Lacey and thought: that shouldn't be too hard!

Thanks in advance. Cheers.

[m1key]

one power cable needs to be connected to a perm 12v supply. and the other to the switched.

best thing to do is buy a cheap volt meter and see what cables are live and what are not.

just do it properly with connectors and dont bodge it with electrical tape !

asda were selling votmeter/ammeters for Ԛ£4.99

m

[notsofast]

Thanks m. I'll defo give that a try. I had assumed that all the wires from the loom are live and the colour codes are as described in the article. I guess that would be too easy.

Cheers.

[nav786]

look in article section. placey has done a write up on audio. it tells you what colour wire is what i think. anyway, the yellow wire from the stereo is the memory wire.

[amit325i]

you should always use a voltmeter to check for polarity voltage etc, as if your not careful you could short your head unit or worse a car component!!

[Adammcf]

Yeah I had to wire my whole head unit from scratch as the previous owner just cut all the wires!!!
I used a voltemeter to find out what was what as the colours of my wires didnt match those in the article above.
A couple of hours and lots of patience later I got it all in with all speakers and memory and aerial working!
I was a happy bunny.

[notsofast]

Thanks again, guys . I'll invest in a volt meter and test out the wires!