On my way home from work last night the sound disappeared on my stereo. I thought it was a problem with the head unit but when I plugged in the original Phillips there was still silence.

I've checked the connections to the rear speakers but haven't taken the door panels off to check the fronts. Is there something else I should be looking at? I'm using the original loom and wiring.

 

Meant to say head unit seems to operate as normal. Can change CD, radio station, volume etc.. but it makes no difference (still silence).

 

I had a similar problem with my Sony head unit...

All seemed to be working fine - tape would play, radio would cause the aerial to go up, but no lights came on on the stereo, and no sound came out. The remote also wouldn't work.

Used the reset button on the stereo and it started to work as normal again.

Not sure how much help this is to you, but thought I would share it with you.

 

It's a Kenwood head unit and I've already tried resetting it. I've noticed my phone car kit has stopped working so I reckon this could be related.

I'll have to wait until the weekend to investigate fully. It's too cold and dark at the mo.

 

It could be as simple as the ISO connector falling out - the speaker connections are all on a separate block to the power connections...

 

Chiark,

Are the ISO blocks the connections into the head unit from the loom? My car is a yr 2000 impreza. It has one white connector block which is on the wiring loom (looks like it has power and speakers together) and this connects to another white connector block that goes into the radio (perhaps this splits into more than one ISO block)?

I've tried two head units now and there's still no sound. Is there another place in the car where all the speaker wires are connected with some sort of connector block?

 

Your car's loom as standard terminates in a wide long white (IIRC) connector which has two rows of pins on it. About two inches wide, by half an inch, or thereabouts from memory.

You will have an adaptor connected to this which gives you ISO connections. There's two blocks that make up the ISO connection - both have two rows of pins, and both are about 3cm wide by 1cm high. Iso connector A has power and other connections, ISO connector B has speaker connections.

The ISO connector will either plug into the back of your h/u, or alternatively connect to the flying connector on your h/u.

To me, it could be as simple as one of the ISO lumps not connecting properly.

If it isn't that, check the h/u speaker outputs and if the H/U is working you've got a fun game of tracing wiring to do. First port of call if the H/U is good would be to check the resistance on each speaker pair of wires.

 

if its a car phone kit like i just installed today, the ISO speaker connection run through a unit that puts incoming call through the speakers by connecting to the speaker ISO then loops back into the head unit? If so the phone speaker unit could be faulty, just connect the speaker ISO back into the head unit just to prove it

 

Could be the phone mute connection faulty.

 

Good point - phone mute normally works by grounding a wire on the back of the head unit. The wire isn't on the iso block. On Kenwood, it's normally brown.

Remove the guff to do with your mobile phone kit and see if that solves it. If it does, at least you know what the problem is

 

I was upgrading my front door speakers, and lost ALL sound, but head unit worked fine. I took front door card off again and played with wires on speaker and HEY-PRESTO sound all round. How does this work then, I mistakenly thought I would only lose sound from that speaker!!! Hope this may help in some way!

 

I suspect a loose connection on one of the front speakers. After investigating the phone car kit I found it didn't have any wires going to the head unit. I banged the door a few times and it started working again. Why would all the speakers stop working if only one is not connected?

 

Warning: theory here to answer your question

If you ground, or dead short, one of the speaker cables then the amp in the h/u will probably do one of two things: go into protection, or self destruct

The protection circuitry will act on all outputs.