Battery not charging; help please

[Matt F]

My 330's battery isn't charging. I went for a drive, and when the battery lost enough juice, it couldn't fire the plugs anymore, and my car left me stranded.

I'd like to take a crack at figuring out if it's the voltage regulators or the alternator myself, but I need a little guidance on how to narrow it down. I've got a multimeter and the factory owner's manual wiring diagram.

How do I proceed? Thanks in advance,

Matt

[tyang]

Hi Matt,

First off, if you ran your battery down dead, make sure you charge it fully before testing your charging system. In fact, get it tested to make sure it's functioning properly by getting it load tested. With really dead batteries, some chargers will not charge them, so make sure you get a fully charged and properly functioning battery before testing the charging system.

I always go with easiest test first. Check the output voltage of your battery connected to your car, but with everything off. It should read about 12 volts with your multimeter at vDC. Next, start your car and put the leads on the battery posts to see what kind of voltage you're getting with the engine running. It should read 13.5-14.5 volts. If it reads less or more than that, something is wrong with your charging system (you probably already figured this part out).

There's a bunch of websites that explain how to troubleshoot your voltage regulator and alternator, One of them is here:
http://www.ehow.com/how_5220979_trouble ... lator.html
Another one is:
http://www.aa1car.com/library/2002/cm10220.htm

You need to figure out what kind of voltage regulator, alternator, charging system you have before you begin diagnosing the problem.

Let us know what you find, and maybe we can walk you through it. Good luck!

Tom

[Matt F]

Thank you Tom, for the quick reply, and for the great website and forum.

I'll take a look at those thread, and then under the hood, and report back with further questions.

Thanks again!

[afwrench]

Hi Matt, if you have any doubt about the viability of the battery replace it. You can get much false info if the battery is in poor but seemingly rechargable condition. I dont know if any portion of you charging circuit is fused but check that as well . A basic test is to energize the field terminal on the alternator and see if it puts out current,you should be able to hear or "feel"the alternator working during this test. If so this usually indicates a good alternator. Look to the simple stuff first ,good battery, good connections ,good ground etc. Good luck ,Mike

[330GT]

... I dont know if any portion of you charging circuit is fused but check that as well ... Good luck ,Mike

Good point Mike, the series II 330 GT voltage regulator is fused. So a blown fuse or bad connection at the fuse panel could cause a loss of charging.

The fuse is the 4th one down on the right side (as facing the fuse panel). There should be +12v on the green wire where connected at the voltage regulator. If not, start looking at the fuse, etc.

[Jimmyr]

Matt, If the voltage to the regulator is OK, then the regulator (red box) could be bad, as they are very likely to fail for no reason. Caution in jumpering wires on the alternator to test it. If you are not sure how to do this remove the alternator and have it checkd out at Autozone or the like - it's free anyway. Rebuilt and updated regulators are available from GT Parts and Rutlands. Jim

[Grigio330GT]

FWIW I replaced by "red" regulator with an aftermarket Transpo regulator. I'll eventually get the red one rebuilt, but for now, I no longer get the "jumpy ammeter". I used an IB305:

http://195.125.241.148/Catalog/E_cat.html

No guarantees that it will work on your car etc...

Dave