ignition light fault

my splitty ignition light comes on and goes off as you'd expect first thing but after a short trip it doesnt come on. Slightly concerning as it obviously also indicates that my fan belt may have fallen off leaving me with no cooling.  
The alternator works as the lights get brighter when i rev it.

any ideas????

Ok. Just put a meter on the the alternator and its reading 12v even when I rev it.

Wip it off and drop it in yo alt-start

is this one of the ones with a plug in regulator ?

oilyT wrote:is this one of the ones with a plug in regulator ?

cant find the regulator  

but whilst removing the alternator, I found the brushes which looked ok. I cleaned up all the internal connections, blew loads of shit out with an airline, put it all back together and its working again

 just a little tlc.