Any auto electricians out there?

[swee'pea99]

Ok, new plea...

I fitted the new unit, by simply using one of those electrical wire-joining strips, matching up the wires by colour. Installed, working, fine. Hoorah. Except...the radio wouldn't work.

Realised what I'd done - attaching all those wires, I'd forgotten to connect the aerial connector. Idiot!

So, removed it again, connected the aerial, decided to check it before re-installing it, nothing. Dead as the proverbial. Checked the connector strip - sure enough, the yellow power cable had detached itself from the strip. No problem. Re-connected it. Still dead. Uh-oh...

I've now rechecked all the connections; they all seem sound. Two of the power leads had fuses on, checked those, fine. Still nothing.

I've been using a multimeter, going back to the original power source cables inside the audio housing space - before all the connectors and wires - but there doesn't seem to be any power at all.

I'm no expert at this stuff (can you tell?) but the way I've been doing it is to jam one of the multimeter pins into the (red or yellow) connector, and touching earth (the door hinge) with the other. That should show a 12v charge +/-, shouldn't it? But nothing. Not so much as a flicker.

I'm really baffled now. I could understand if I'd screwed up the connections, but no power at the source? That just doesn't make sense to me. Does it make sense to anyone else?

And advice/suggestions much appreciated.

 

[swee'pea99]

Scrub that - I had the multimeter on the wrong setting. There is power...it just won't work. I'll get new fuses tomorrow and see if that helps. *sigh*

 

[swee'pea99]

Ok, if I check the voltage on the red lead I get 12, but on the yellow lead I get 1.7. Does that suggest anything?

 

[swee'pea99]

Now here's an odd thing...

I went back to have another look at the instructions in case there was anything helpful, and I came across this diagram:

Now, I know that when I removed the old unit and put in this one, I just did it 'like for like', which among other things meant that I connected red to red and yellow to yellow. Why would you do anything else?

But after looking at this, I thought, why not try switching them over, so red goes to yellow and yellow to red, and see what happens. So I did that, and as soon as I connected the red (car side) to the yellow (unit side), the unit - previously dead as a dodo, made this brief but very distinct groaning noise. Only lasted half a second if that, but it was the first sign of life since it 'died'. No lights, no sound from the speakers, no *functional* life...but a distinct groan. Which repeats every time I make that connection (tho' nothing else happens).

Suggest anything?

 

[swee'pea99]

[QUOTE 2992274, member: 45"]You're sorted now, bit an old credit card cut into strips does the trick.[/QUOTE]
Ah! "no *functional* life...but a distinct groan"

I actually got the old one out a week and some ago. I'm trying to get the new one in now. Or rather on. In I can do. It's the on I'm having problems with.

 

[simon the viking]

Its something to do with switched and permanents lives try joining both red and yellow on stereo together and connecting them to the live on the car that is live when ignition is off but if you do this you will need to remember to take the front off or you may drain the battery

 

[swee'pea99]

Actually there was a diagram along those lines just below the ones I posted:

I didn't do it because the previous unit hadn't been wired that way, so I presumed it couldn't be right.(Needless to say, I have no idea what 'ACC position' means.)

Have to say, I prefer it to just come on when I turn the ignition...surely it must be able to do that if the last one could? (I really can't have it so I need to take the front off every time - first., 'cos it's a pain, second, 'cos I'm bound to forget, and killing the battery would be an even bigger pain.

 

[simon the viking]

Actually there was a diagram along those lines just below the ones I posted:
View attachment 40570

I didn't do it because the previous unit hadn't been wired that way, so I presumed it couldn't be right.(Needless to say, I have no idea what 'ACC position' means.)

Have to say, I prefer it to just come on when I turn the ignition...surely it must be able to do that if the last one could? (I really can't have it so I need to take the front off every time - first., 'cos it's a pain, second, 'cos I'm bound to forget, and killing the battery would be an even bigger pain.

Accs position means ignition switch (it would come on 1 click before starting engine) have you switched red and yellow yet if you havent try that as volkswagons (and vauxhalls) have the ignition live and permanent live the wrong way round

 

[swee'pea99]

Stupid is my middle name.

As to the accs position post, I did try swapping them round - as posted half an hour back:

"Now, I know that when I removed the old unit and put in this one, I just did it 'like for like', which among other things meant that I connected red to red and yellow to yellow. Why would you do anything else?

But after looking at this, I thought, why not try switching them over, so red goes to yellow and yellow to red, and see what happens. So I did that, and as soon as I connected the red (car side) to the yellow (unit side), the unit - previously dead as a dodo, made this brief but very distinct groaning noise. Only lasted half a second if that, but it was the first sign of life since it 'died'. No lights, no sound from the speakers, no *functional* life...but a distinct groan. Which repeats every time I make that connection (tho' nothing else happens)."

As to multimetering - I'll do that. And I have sussed out that the black is earth, so that should save the bodywork.

 

[swee'pea99]

Ok, it gets odder. I've just checked - three times, to be sure, and - the red shows 12v, regardless of whether the ingition's on or not. But the yellow shows zero, again regardless. Tho' I'm certain it was showing 1.7v earlier. As in certain certain. I know because I was struck by what an odd figure it was.

 

[swee'pea99]

[QUOTE 2992436, member: 45"]Some manfacturers, VAG for example, wire their looms differently so that the ignition live and permanent live are the other way around. Get it wrong and you lose your settings every time you turn off the ignition.

Your best bet is to find an online forum for your car and ask them.[/QUOTE]
Interesting. It is a Golf, so...

It's a good suggestion to find a specific VW forum...it's just that I've generally been able to find good advice round here on just about anything, at a level I can understand. Very often if I go to a specialist forum, they very soon start talking over my head.

 

[simon the viking]

Have you checked the car fuse box? you could have blown a fuse earlier..... does the cigar lighter work that is sometimes on the same fuse

 

[swee'pea99]

Have you checked the car fuse box? you could have blown a fuse earlier..... does the cigar lighter work that is sometimes on the same fuse

Thanks - that's a good thought. I will check it out tomorrow...it's too dark right now to go on with this. It's bad enough in the daylight....

As to the 1.7v, I definitely had it on DC - it was on the same setting when it gave 12v for the red and 1.7 for the yellow. And tho' I can absolutely see the logic behind finding the wire that's dead then live depending on whether the ignition's on, all I can say right now is, when I tried earlier, I couldn't find one. This makes about as much sense to me as it does to you, but that's how it was.

Many thanks for all help and suggestions - really appreciate it. To be continued...

 

[swee'pea99]

Ok, minor update (I haven't been able to spend much time out there over the last couple of days, but, FWIW) First, I've changed all three fuses. No difference.

I have also checked out the car main fuse box, or rather, Haynes says one fuse covers the radio and the cig lighter, and the cig lighter socket is definitely live, so that seems to rule that out as the problem.

I was told by the guy who sold me the fuses that the yellow wire should carry the current - hence the in-line 15amp fuse - the red should be connected to the ignition, to turn off the unit when the ignition's off. But when I test with the micrometer, the red shows 12v, the yellow, zero. That can't be right, right? So would I be right in thinking that I need to keep unravelling insulation tape and exposing wires, and trace progressively back along that yellow wire till I find a place where I do get a reading, then fix whatever problem is preventing that getting through?

 

[swee'pea99]

Sorry, I should've mentioned - the 12v and the zero seem to both stay the same regardless of whether the ignition's off or on. And there are fuses on both wires - 15amp on the yellow, 1amp on the red.