Battery light comes on when revving high

[lil killer]

Whenever I rev over around 4500-4700 my battery light comes on on my dash. Anyone know why?

 

[Kilgore Trout]

Take the car to AutoZone and have the charging system tested for free in the parking lot.

 

[GunmeatalGT]

yes, its either your bat or alt is on its way out

 

[clockstopper]

doesnt the charging system kinda turn itself off, or stop charging at high revs? If so, when it stops charging, you could be seeing a failing battery? I'm probably wrong, but it sounds real good.

 

[goshia]

do you have a smaller under pulley installed?

 

[LI98GTStang]

All good suggestions. Could the belt be slipping?

 

[race-stang]

your belt is slipping. how old is it??

 

[85 Coupe 5.0]

Had the same problem. Was racing one day, and alt light started to come on above 3K or so. Mine would quit chaging altogether, voltage would drop off and everything. Fine if I stayed below 3K or so. I replaced the alt, problem solved. Just my experience.

 

[Mike97gt]

many times a seized up belt tensioner can cause this. pull on your belt or use a ratchet and see if the tensioner arm moves if not it's frozen