In article , Steve
says...

hi,
Fiat Punto 1.2 petrol w reg year 2000 has apparent varying light brightness
to headlights and interior lights.
when stationary and rev engine lights tend to brighten then dim. this
applies also to interior lights. When driving along the road in darkness,
the lights tend to vary in brightness.
any ideas ?
Steve for a friend.

Yep. Its working properly. When you rev the engine, the alternator
provides more current and a raise in voltage which results in brighter
lights although when driving down the road it shouldn't be massively
noticable.

Get the alternator tested.

--
Conor

I'm not prejudiced. I hate everybody equally.