dimming lights at high RPM

[VTExplorer]

Hi everyone, I'd first like to say wow what an awesome site. I wish I had found it sooner!

I have a '96 XLT 5-speed, 97k miles. When you rev the engine past 4000-4200 rpm, the headlights and dash lights all dim down. Is this a symptom of a terminally ill alternator?

Thanks.....Alex

 

[RiverRat]

It could be a alternator. The brushes wear and don't make good contact sometimes. Is the belt slipping at all?

 

[VTExplorer]

Nope the belt doesn't slip at all

 

[VTExplorer]

I checked the current at the battery today, found there was over 20 volts at idle. Time for a new voltage regulator.

 

[MattPersman]

you probably want to get new brushes, and rear housing bearing while you have it open to replace those too. don't forget to clock it in the right position when you put it back together