Alternator ??

[Whitehot]

Got the Mustang out today... and after little driving, battery light went on :( .... Remembering form last fall, when that happened, the Alt got changed last fall... and the battery... What would make it do it again, would heavy duty alt work better,... Take a few higher revs than stock size Alt??... is there an easy way of telling what is wrong, batey not accepting a charge?? or... Alt gone again?? ....

[ZR]

Check voltage output with a meter. Although, possible for output to be on the money and the alt still have a diode or similar issue internally. Before condemning it, should also check all battery and ground connections both at the body and on the engine itself, especially main ground on the block.

[RedSN]

^^^ground cable was what I was thinking.