Ignition light glimmering

[kenton]

Evening all,
While out in the Westy at night I noticed the ignition light was slightly illuminated, (you cant see it in daylight). Its a denso alternator putting out 14.5v on tickover. Battery also shows a good charge.
How can the light get a neg supply with the alternator charging? Its only a tiny glimmer but I'd like to fix it. Any Ideas??
K

[b33fy]

Does it make any difference with the lights on or off? Thinking of possible feedback from another circuit. I rewired mine to be totally independent to any other circuit.

A quick search also suggests trying a bulb with a different resistance. New one on me tbh.

[kenton]

Mike, no difference with the lights on or off

[kenton]

Just been googling. A bad alternator earth could be a cause. I'll add a temporary earth cable and try it again.

[Red27]

I had something like that, just before I lost all electrics and we had to coast into a gap betweent the cones on the run down to the Dartfort toll booths during a Friday rush hour, with the sun behind us - hence why the glimmering hadn't been noticed until I said "what bad thing can happen ......" Oh. Mark will remember that, we were due at his ready for a trip to Ypres the next day. He kindly came out to supervise Paul and the RAC man. Alternator had shaken itself to bits inside, due to the inevitable Tiger dodgy alternator bracket scenario.

[ChrisS]

Could also be a sign that the diode pack that feeds the onboard regulator has lost a phase. This wouldn't neccesarily result in no charging with lighter loads, depending on the capacity of the alternator and how much you are drawing.

If the earth doesn't help, might be worth trying a higer wattage indicator lamp as suggested.

[ChrisL]

does it go away when you rev the engine?

[PaddyX21]

Just been googling. A bad alternator earth could be a cause. I'll add a temporary earth cable and try it again.

I think this is exactly what was wrong with my last one - only if earthed direct to the body of the alternator it was fine, so there must have been a bad connection internally.
I'd have looked for it if it wasn't brand new, I ended up just getting it replaced free of charge.

Worth a poke about I'd say

[David T]

My ALT light started this ever since I fitted my Denso mini alternator. It's very faint and only visible when a dark night. No other issues, so I just consider it a 'feature'.

[Tony C]

Worth a poke about I'd say

Indeed