generator light on for several minutes.

Hi all.
Jumped in to the car this morning and the generator light remained on as i drove away.
pulled over checked the fan belt , checked the belt tension all well.
Hopped back in and it remained on as i drove for several minutes and then went out .
This evening same thing as i left work, but feel the gen light was on for much longer , again it went out after some time.
Where do i start looking to resolve this ??What is needed to remedy this ??

Brushes worn out or sticking.

DH

thanks , for answering, so just move the springs on the brushes about? i`ll inspect tomorrow during the day and inspect the brushs.
i will post what i discover tomorrow

give em a bit of a push down n may sort it or maybe need replacing.. 1st port of call

Thanks for the reply , i shall try tomorrow morning and see the outcome and post.

Good news !!!
Thanks for the advice , spot on ..
Jostled the brushes about a little and all is well.
Brush length is good, the car starts without the gen light glaring ..Many thanks again..