[GUMBALL]

OK,

Jon / Chris,

The problem occurs when the brake lights are on.

findings so far...

All earths are fine.

Battery is fine.

Charging system is fine.

However, I have discovered that if I take the feed (at the fusebox) direct from another source (the one that comes from the starter motor and therefore a much heavier cable) and connect it to the feed for the indicators (the ignition circuit) the problem goes away.
Now this circuit feeds lots of things anyway, so it's not been easy to find what's causing it.

Or, do I assume that it's caused by the cable not being man enough for the job? (This is the original Dax loom, so I assume it was the correct cable in the first place) and replace with a larger cable. Making the assumption it has always been the same.

Interestingly, it doesn't happen with the hazards on as they are not fed by the ignition circuit.

What next???

Sean