not charging

my mates 3.5 efi wont charge, when running the battery light is on and will eventually die due the non spark with the battery having no power left.
it has since has a new alt, new battery, all the earths checked, what cant his be? any clues?
next move is to put a new live feed from the starter to the alt, also from the starter to the battery, it has always been wired up light this since he owned it anf gonn relace those wires to see if there are any breaks in them aswell, is this thr right way in wich it should be set up? cheers lads.

As you've done all that then there's not much left except a wiring fault.

Do what you said and fit a new live wire from alt to battery, also, unplug the charge warning wire from the alt and turn the ignition on, the light should not come on. if it does then there is a short to earth on the charge light wiring, this will stop the alternator from charging.

Check all maxi fuses and fuseable links to the battery.

much appreciated, will get back if no further progress is made.