(another) Weird Highline issue

[Ps3000]

Put the highline back into my car (it had an android DD unit fitted).

Once I had properly figured out (with help from folk on here) where everything went, the radio etc fired up fine, and as an added bonus, I had sound from all four doors. The driver's door never had sound when the 'droid unit was in - although we know the unit was OK.

About 25 mins along my first drive, the unit lost all sound. It appeared to be working OK, displays were fine, the tuning worked etc. Apart from very occasional bursts (and only two or three) of sound on the way home, it remained dead.

At home, after a "rest" it worked ok - but opening the driver's door seems to upset it - for a while I could get it to cut out consistently (total audio loss) by opening the driver's door beyond a certain point. Now it's started working again.

I can't see anything in the drivers door wiring that would obviously cause this - anyone got any bright ideas what could be causing it? I have checked all the wiring in the boot (twice).

[Avulon]

If it's all speakers cutting out, then I'd look at the speaker wiring in that door, it must be shorting to earth intermittently, that would cause the amplifier chip (in the radio module) to shut down in self-protection against the short.

Remove door card and speaker and with everything off (disconnect battery, remembering to shut down nav drive first). connect a multimeter set to ohms across the speaker wires now open and close the doors: I'm guessing that you'll see the ohms drop to zero at one point. (having removed the speaker and disturbed the wires you may have to wiggle them around a bit.

[Ps3000]

Good point - that would explain the lack of sound in that door - maybe the other head unit can shut down channels selectively

[Avulon]

The standard Rover radio unit has a single (stereo) amplifier chip, one of the TDA range iirc, and that will have short circuit protection. The other head unit probably had some other arrangement. I'm not saying that it's a guaranteed thing, but all evidence given points to a problem with the speaker wiring in or close to the door.

[Ps3000]

OK, trying to second guess this issue, I found an ISO - ISO loom I had lying around from another project - all wires straight through.

So I reasoned that if I placed that in line, (having snipped front right entirely +ve and -ve) that would isolate the front drivers door and allow the rest to work OK.

Unfortunately, that theory didn't work out, as the unit booted up fine but still refused to issue any sound at all.

Is my logic right - the (speaker bit) of the ISO socket behind the ashtray brings the speaker connections "back" from the unit in the boot? Then the Speaker ISO plug takes the speaker connections the final bit to each door. I assume that's how it's possible to connect direct to the speakers by plugging the Speaker ISO into the back of a standard head unit?

After reconnecting the snipped wires (from my spare straight through loom) and plugging the ISOs into a known good head unit, the driver's door speakers were still dead - but I can't help thinking I am missing a trick somewhere here.

[Avulon]

I'm not 100% certain but I think the loom from front to back branches off the wiring for the speakers. This means you can connect and amp output at either end of the loom. Does that make sense? I think the only way to make certain is to find a connector between the main ICE loom and the door loom and disconnect it there. I'll take a look at the wiring diagrams tomorrow evening if you're still having problems.

P.S the wiring diagram shows the speakers connecting to the 16 pin (round pin) connector in the centre console. Connectors 2 and 11 looks like blue and purple for the front Right, the only other connector shown is the one at the door pillar.