Hi,

The light that looks suspiciously like a battery has been coming on intermittently whilst driving, I checked the manual which says it's the dynamo warning light which should come on when I turn on the ignition, which it doesn't do, and shouldn't be on at all whilst driving.

The strange thing is that the light stays on even after I've turned the ignition off, and has occasional greeted me in the mornings before I go to work, it usually goes out after a few miles. Perhaps even more peculiar is it's tendency to be quite dim, kind of like it's only half turned on.

Does anyone know what would cause this?

Thanks.

Having a old battery fitted might be a problem.

If an alternator is failing it could cause this.

Alternator pulley could be on its way out.

Depending on what model you have, there's two wires that run alongside the gearbox from the alternator, they have a habit f breaking and snapping off causing problems.

The good news is almost any garage can check all of the above very easily and cheaply. A quick drop test on the battery can eliminate that, then a quick check on the alternator output would help see If its working or not.

What engine is it? If it's a diesel the alternator sense wire would be my first thought as Holmesie suggests.

http://www.briskoda.net/forums/topic/247393-dfm-wiring-aka-alternator-sense-wire-asr-faults-no-battery-light-alternator-not-charging-etc/