sweetbeats

So the battery light on the dash keeps coming on intermittently. I've got over 13V at the battery when the engine is running, and I've checked connections at the battery, alternator and starter. All are clean and tight. Suggestions?

oxfordgt

You should have 12.6 with the engine off and 14.5 with the engine running. Any less and you have a charging problem.

Z28KLR

Could also be worn shaft bearings on the alternator. I had one go bad a couple years ago, same thing as you're having with the intermittent light and voltage checked at battery terminals was only a hair low; iirc it fluctuated between about 13.5 to 14.0. When I removed the belt and spun the alt pulley by hand I noticed a bit of endplay in it, probably enough that the internals would move out of good alignment with each other and trigger the light to come on. New alternator obviously was the fix.

Could also be bad diodes in the alternator, but that typically manifests itself in the form of random misfire (P0316) dtc or camshaft position sensor dtc.

I would suggest removing the alternator and taking it somewhere to be bench tested.

oxfordgt

I had an aftermarket alt on my old 2v and the post was crappy on it and gave me the random battery light. Fixed the connection and no more problems.

Gary Ugarek

I just had the same issue. Swapped the Alternator and problem solved.

While I did that I also added some MSD Coils and NGK plugs

jwog666

if the connections are clean, your alt is most likely bad, the brushes tend to wear out and damage the slip rings on the shaft, take it out and run it to advanced/autozone etc. and have them test it on their tester, its free, then you will know for sure if you have a bad unit or not.

oxfordgt

No need to take it off, Advanced has the ability to test it on your car.

sweetbeats

Thanks everybody. I appreciate the replies/info. I'm fairly certain the alternator is original to the car, and even though the car has under 60,000 miles on it, it's now almost 15 years old and sounds like that component is the place to start. Thanks again. I'll update as I get more info.

Derf00

Bad alt,

My old 00 V6 did the same thing. I ended up pulling the alt off and having it bench tested. 3 out of 5 tests showed the alt failing. (first passed it, second failed it, third passed it, 4th and 5th failed it). Replaced the alt, problem solved.

sweetbeats

Battery at rest (engine off) is 12.5V. With the engine running there is 14+V at the battery. Now, that's when the battery light is NOT glowing in the instrument cluster. The thing to do would be to test it when the battery light is glowing.