Heyo everybody, thank you for any expert opinions I may find.

My Grand AM can hold power and will drive. However, while driving my battery light is on, and the car will eventually run out of power. The time I can drive for seems to be shortening.

It seems like an alternator issue, so I replaced my alternator. However even after replacing the new one, the issue is still happening.

I was having problems with my starter, the housing was broken. I didn't have much money at the time, so I ziptied the housing in place, and it ran perfectly. I did this a couple months ago, I don't know if this could be causing my problem now?

Finally, there's the battery. I don't know if a damaged battery could cause this? I've charged it quite a few times now and it seems to stop early while charging. Still, partsource says the battery tests fine, and I don't know if a poor battery could cause this.

I don't know what to check next. I would greatly appreciate if someone may have experience with this.

  • A battery could cause that, but other issues seem more likely to me. Chiefly, insufficient alternator rotation, or incorrect alternator. The battery light typically indicates alternator faults, so that would be thw #1 suspect. Additionally, aftermarket or damaged accessories could cause too much continuous draw, although they would also likely have to be wired wrongly if it does while driving. One way to check, is do you notice any accessory commonality? Try shutting off everything non-essential (one at a time) and see if any change the condition. Otherwise, double check the alternator. Nov 20, 2019 at 1:08
  • I had a similar problem with my '96 VW Polo. The battery drained incredibly fast and even hocking it up to a charger every other night didn't help. The problem in my case was a broken ignition coil. More precisely the 20-year-old brittle plastic housing of the coil was cracked and moisture got inside. This probably caused leakage current which drained the battery over time. I've noticed that the battery drains especially fast when driving in the rain. In my case, it was a 25€ part and I fixed it myself but finding the component which causes this problem may take luck or an expensive mechanic.
    – GittingGud
    Nov 20, 2019 at 10:50

1 Answer 1


I don't have anything for 2000 Grand am but I did see in a diagram for an 03 (that uses same generation of ecu), a "Turn on Signal". I'm not that familiar with these early gen gm ecu's but If I was you I would find out for sure if the regulator is in alternator or in the ecu. IF its in the ecu I would start to consider it could be faulty which is a common failure in ecu's that do control the regulation.

gen signal

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