Speaker issues
 

My good Sport has just developed an issue with the sound system - namely no sound out of the places Volvo put speakers (dash, front doors, rear doors and D-pillar). All of them went off simultaneously. Sub still thumping.

This is taking place with three different head units (two different Sony ones and a JVC one. It is taking place with three different ISO-to-Volvo adaptors - and two different Sony-to-ISO adapters and of course the JVC-to-ISO adaptor.

So, first thought - a speaker is short and the head units are protecting themselves. BUT with a multimeter all the speaker wires at the head unit end show about 4 Ohms (as they should).

Odder still, yesterday on my way to shout at Halfrauds (quite unjustifiably) on my drive all head units fine - and the one in the car went quiet again halfway to Halfrauds. All head units test OK at Halfrauds, but none work correctly in the car.

Now to my mind this suggests that somewhere a plug-in connector in the loom is wiggling about (since I've ruled out the adaptors). Is there one, maybe somewhere under the dash? I hate taking the dash out!

Next possibility, a wire somewhere has been rubbing on a metal edge. Insulation worn, intermittent short to earth, head units go into self-protect mode. This will mean removing all the door cards, tracing the wires to the D-pillar speakers, hoiking out the door speakers and dash speakers, and poking things up door pillars until I find the culprit. Bah.

Open to helpful suggestions where to start!

Disconnect the speakers (at the headend) and then connect one by one
Drive for a few days on each speaker
You'll soon find the culprit.

Have you removed or bypassed the factory amp? If not it might have failed. I believe it's located behind the driver's kick panel, but I've never had to mess with one myself.

Factory Amp
 

I have the correct adaptor leads but IIRC there was no separate amp on a 96 car.

Wiggle it, just a little bit
 

So far totally intermittent - some mornings the sound system is fine, some only the sub comes on, some days it starts OK and goes off while I am driving. No joins in the loom as far back as my arms can reach, no apparent correlation between function and wiggling, function and temperature, function and bumpy roads, function and percussive persuasion to the console or dashboard. ISO to tails adapter ordered so that I can try isolating one set of speakers at a time - but until the fault becomes constant rather than intermittent I won't know if I've fond the fault!

is it just the sound or does the head unit do anything when the sound goes off?

Just sound
 

The head unit functions normally at almost all times. The fault is that sound vanishes from the usual Volvo speakers and just comes from the sub. But it was good all day today!

Loudspeaker problems
 

My v90 started to develop a similar problem where the left side speakers were very quiet. After some time I tracked the problem to the volume control on the stereo, and in particular it is linked to the automatic volume control which adjusts the volume in relation to the speed. I stripped the radio and cleaned the switch with maplin switch cleaner. Problem dissapeared for a year or so but returned, so, as it is probably impossible to buy a new control for the radio, I just turn the volume control round and round rapidly until sound returns.

Not that
 

It ain't that because in the Sport Edition in question there is no AVC. I might do some prodding this week.

Check your doors. I had a short in my driver's side door loom - the cables were rubbing against each other in the rubber boot that protects them as they go from the body to the door. It caused intermittent output on the driver's side speaker, and eventually both stopped working and I had to rewire it (and also rewire the horrific mess that a previous owner made behind the stereo).