Battery Light above 4,000 RPM

[skreel]

I have a 95GT, when my RPMs go over 4,000 RPM my battery light comes on and it doesn't seem like it's getting as much power. The car runs fine otherwise. Does anyone have any suggestions as to what may be causing this?

Thanks in advance!

 

[95-stang]

If the fan belts not slipping at high rpm, i would have the alternator tested.

 

[Mr Jones 4.6]

I would have to agree, go get the alternator checked and see what they say.

 

[stang94X]

i agree with the above about the belt slipping so i would check that out and it could also be that the voltage regulator on the back of the alternator is starting to go bad

 

[skreel]

Thanks for the suggestions. Is there an easy way to determine if the belt is slipping? If I just watch it while someone revs the engine will it be noticeable?

 

[95-stang]

Possibly, there's a chance you might see it, the tensioner operates within a certain range, i think there's 2 notches actually on it.
If you have under drive pullies, or its had a new alternator at some point, the pulley is an interference fit, the alternator pulley can slip if the big nut [about 24mm ] is'nt tight, but you need an airgun to check that its on tight.
See if there's any fine rubber particles about also, that can indicate the belt is slipping or the tensioner spring is weak.