Very faint battery light - constant

[akwoods]

Hi,

My E53 diesel has a really dim/faint battery light on at all times while running. I was concerned it was the alternator so took it to the mechanic and they tested the alternator output, which was a consistent 14v during the test. The light is so dim you can’t see it when driving during the day, it’s more visible at night but dim.

The starter motor was replaced by the mechanic about 2 weeks ago and I thought maybe it was a bad earth from the new starter motor, but the mechanic checked this and it isn’t the problem.

The light is constant, not flashing, and doesn’t get brighter even under load (headlights, fan, air con, etc) just always the same. The alternator had new brushes installed 12 months ago, so I thought maybe the voltage regulator was dying, but the voltage is consistent. Any suggestions?