Ignition light

[wurlitzer]

Driving back 50 miles from getting my brakes repaired I was almost home when the ignition light came on.I stopped to check the fan belt hadn't broken,it was intact but because the engine was hot I didn't check the tension.As I revved up the light became brighter,for the last mile home it came on and off a couple of times,I seemed to remember reading years ago if the ignition light glowed brighter it meant something,any ideas what it might be before I take the Dynamo out to check the brushes?

[philthehill]

First check the tension of the fan belt. It may worn and slipping.
I would also check the condition of the brushes - do you have an early dynamo with the brush inspection cover? If you have you can check the condition of the brushes and commutator without removing the dynamo.
The later dynamos unfortunately do not have the bush and commutator inspection facility and the dynamo has to be removed for brush and commutator examination.
Phil