Alternator failure?

Hi Newbie here, my daughter has just bought her first Golf Clipper 1989 1.8, having more or less thrown my tools away (got lazy with newer cars). I am faced with dusting them off (actually bought a new set yesterday) and getting oily up to my armpits again!
    Anyway, we drove it back from Edinburgh fine but ten days later it has stopped charging, I think, although the alternator light goes off on start up? What causes a sudden charging failure, is there a fuse or relay that may have failed.
Thanks in advance (ive heard good things about this club) Oh yes and a wiring diagram link would be nice
Darren

Hi and welcome aboard.

Alternator failure is usually down to a couple of things really Poor earth, worn out brush pack or regulator.

Plus the blue exciter wire becoming broken. It's on the back of alternator.

I would clean up all the cable connection points inc those to the chassis to start with and with all electrically things off, such as lights, heated rear screen, radio etc, test what voltage you are getting between the battery terminals usually around 13-14V.

It seems straight forward enough to replace the brush pack. Remove alternator, undo the 2 screws either side of the regulator pack lift out carefully, using some contact cleaner clean all contact points the brushes run on too.
Plus the conatcts that any electrical connectors go to aswell.

Just make sure your battery isn't duff and if it's a non sealed type the electolite level is okay.

Just an update, weirdly the alternator was still charging but at only about 11.5 volts not enough to sustain the battery. Got a new regulator from GSF parts for £16 plus vat, cleaned the alternator replaced the regulator and refitted. Woo hoo it worked, now we have a nice 14.5 volts across the battery terminals. Thanks for the information and help, carb next on the list!
Regards
Darren

All working well, except the amp in the boot turns off as soon as the revs hits 2000 rpm, most bizarre!!
Darren