Alternator Light On - Goes off on restart

[in_transit_vanlife]

Hi All
I have a 2008 Mk 7 Transit with 2.4 tdi engine. Alternator was replaced last year but has now on occasions when starting from overnight the alternator light stays on. Normally I only notice the light is still on after driving a few hundred meters down the road. I stop turn off and restart and normally the light will go out. Sometimes it might take a km or 2 of driving before a restart turns the light off. Thinking it has been on mornings where it is a bit fresh, maybe a bit damp overnight?? Never had this issue later in day or other times when starting up. Volt meter shows normal output when alternator light isnt on.
Any clues where to look for a wiring or connection issue. Wonder if the alternator clutch pulley not engaging till warm or do they not work like that?

Thanks

[metalworker0]

1.Loose belt that plays up when damp and slips on pulleys,
2. Belt in poor condition,
3 Corrosion inside back of alternator on the electronics, that holds moisture .. until its warmed up and dries.
4. Bearing on alternator, on its way, out causing belt to slip.
5. Could be all - battery terminals , earths , thick lives .. that are corroded where they bolt on .

if slippage of belt occurs caused by 1,2 and 4, it will usually be heard as a squealing / shrieking noise

all the best.mark

[in_transit_vanlife]

Thanks Mark
Belt in good condition, tensioner & pulley replaced last year, no noises at all, doesnt appear loose so thinking will look at 3 & 5. Will get underneath and check wiring and terminals where I can.

[MinorMatt]

I would have a look at the clutch in the alternator pulley - they normally either work or don't - but you could end up with a condition where it doens't grab unless its warm?

[andz327]

The alternator voltage regulator is basically open to the elements on the back of it , and cleaning the contacts/brushes can sometimes help or replace if worn out, easy job

Sent from my SM-G990B using Tapatalk

[in_transit_vanlife]

Thanks all will investigate further.