GrandAm Battery light coming on not sure why

Hello Everyone,
I have a 2000 Pontiac Grand Am SE 2.4L 4cyl automatic. The car had been sitting for about 6 months and I had to replace the starter. Finally a day off, replaced starter, charged battery, the heavens opened and the angels sang when it fired right up. Let car run for about 20 minutes sounded great. Noticed that the battery light came on. Took car to give it a much needed bath and when finished, was slammed back down to earth when the car wouldn't start. Day 2... Remove alternator and have it checked. Autozone says it's good, I replaced the serpentine belt because I noticed some small fraying in a spot. Tensioner was great. Charge up car and it starts. Try to restart it and not enough power. Now a week later, I am thinking battery or fusable link or bad wire. I pull the battery and have AutoZone check. Battery is bad. I replaced battery and "The Pickle" started right up! (Can you guess what color she is *laughing) Enjoying her gentle purring once again I am dragged back to reality when the alarm bell sounds and the battery light goes off again. I am now thinking fusable link and wire once again. Does anyone have any ideas? They say patience is a virtue but I am starting to think I am not a very virtuous woman. Any help or advice that you could give me would be greatly appreciated. Thank you and have an awesome day!

You need voltmeter on the battery static. Starting voltage(need a helper) Charging/Running voltage with all accessories off. Charging voltage with everything on. Charging voltage reving engine. Clean all battery cables and check they are tight.

Have to agree with the Kat....

A fully charged battery will read 12.6 volts with a voltmeter across it...Have someone crank the car and notice voltage.....should not drop below 10 volts....

Next let the car start and run....on a cold engine, the voltage should be around 14 volts and as it warms up and the rpms drop, so will the voltage, to around 13 volts....

Now turn on the lights and rear defogger and fan blower on high, and voltage should drop to around 12 volts.....rev the engine to 2000, and voltage should increase to 13 volts.......

If you are not getting these voltages, then it looks like an alternator.....however with the engine now off, and using a test light, not a voltmeter, attach the negative end to the bat neg terminal, and the probe end to the bat pos terminal......notice the brightness....now take the probe end and touch the large red cable attached to the back of the alternator....should be the same brightness.....if much less or not at all, you probably have a fuseable link problem....

Many times when an alternator is removed, it tests out ok....because it is cold....alternators tend to test bad on hot engines, as they warm up, and under a load....

Thank you Kat and TechII !!! I will be trying this today or tomorrow and get back to you. I appreciate your time and instruction! Hope you both are having a great day!

Okay everyone, I have checked the alternator, the fuseable link and they are okay. But I did notice that the new starter I just put in is making noise and is running really hot. The wires are hooked up correctly. Could this be why my battery light is coming on? It is draining power? I am just stumped.

Sounds like your replacement starter is the culprit. It shouldn't be hot when the motor is cold, if it is then it has an internal short and is what is draining your battery. Try disconnecting the starter and hooking up an ammeter between the starter and the power feeds. There should not be any draw at all. Also, test between the alternator and the red wire attached to the alternator. Should be no draw there either. Good luck.

Hello again,

I had to replace the new starter, it was bad. That issue solved but not the one with my charging system light. I just replaced the alternator. Checked the Alternator fuse and it is okay. Checked the fusible link from alternator to starter 3 times and I get nothing. Check it again today and I get voltage. It does not look burnt but at this point it is the only thing that I can think of. Next question.... Can I make my own fusible link or do I need to get one from the parts house? This car is giving me more gray hairs than my children and husband combined! *laughing

Thank you everyone for your great advice it truly is appreciated!!!