1stgear

Sometimes when I am driving my headlights will dim and then go back to normal brightness. The car is under constant throttle. Any ideas what could be causing this?

I've also noticed that when the car idliing and is at normal operating temp, the battery light will go on and off until I give the car some throttle. I don't know if this is related to the lights or not.

Any help is appreciated.

theiceman

.. nothing is ever a coincidence .... your alternator / regulator is dying my friend .... when the alternator kicks out you are dropping from about the 13.5 -14 that the alternator kicks out to the 12 volts the battery kicks out , the lights then dim and you are running the entire car off the abttery.

of course you need to check and clean all your connections carefully to the alternator and battery , also check the grounds in the car, but my money says you are about to have your alternator rebuilt. Just makes sure they use a quality regulator when they do it , not the chineese crap .... no offense to our asian friends

i have a voltmeter wired into my car so iknow exactly how things should run ... if you have the opportunity you should wire one in , even temporarily , this will tell you everything.

oh one more point , don't forget the battery , if you have a cell short it can do werid things , but that is fairly easy to bench test . but if it were my money ( and it isn't) i would put a fresh battery in when I did the alternator ....

Good luck and let us know how it goes ..

wellcraft290

Is your battery low? It could be your alternator charging yoru battery and using that power for this. Just a thought.

1stgear

I'll check this first. I'm hoping it's not the alternator... but that's what I fear the issue is.

wwest

Intermittently shorted cell in the battery. Alternator might also be a problem but a good battery would prevent the lights from INSTANTLY going from bright to dim. But always confirm good ground connections EVERYWHERE.

GothingNC

Could it be a slipping alternator belt?

John

rusnak

That's a great signature picture !!

1stgear

Thanks! I love that movie.

MUSSBERGER

That would be too easy.

Scott Lenger

That was same symptoms I had as my 2 weeks notice that my alternator was quitting...

Address the issue now so it can be at the time and place of your choosing.

rusnak

I think there is some great advice in this thread.

You should use a small brass brush to clean your battery terminals, top up the electrolyte and charge battery, after a rest and a few cranks, connect a voltmeter to see if it's holding charge. Re-read post #2, then start up the car and check the voltage at idle with all accessories turned off, then with lights and radio on.

The 3.2 positive battery terminal for some weird reason tends to build up corrosive salt that needs to be cleaned off. Eventually you may need to cut off the old positive battery clamp and install a new one.