So the GS I've had for about 8 months. When I bought the car, the battery had died and the seller jumped the car, got it running, and I drove it home the next day. Everything seemed fine. I can't remember when it started, but one day the battery light came on. Checked voltage and it was fine, car ran and drove fine, so I drove it. The light only comes on when I am sitting at idle for a minute or two. Some days I can drive it on my daily commute of 100 miles round trip without it coming on. If I get a long red light, the battery light pops on.
So I had the local parts store check it. First thing they checked was the battery and they said it was bad. No biggie after sitting dead for a couple months, that is to be expected. So I changed it out with the one from my truck. Battery light still comes on. So I figure alternator. Get another one and changed it out. Battery light still comes on. On a cold start I am getting 14.5V. Both batteries hold over 12.8V when turned off for over a week. Warm idle the voltage does drop some, but never below 13.5V, on either alternator.
I checked the connections to the battery. They are clean and tight. I checked all the grounds under the hood and they looked good. Just for good measure, I cleaned the paint off down to bare metal, wire brushed the bolts, and reinstalled. Still the same issue with the light coming on.
So next thing, the engine to body ground is tiny IMO. And the alternator uses that as its ground back to the battery to charge. So I installed a larger 4 ga wire from the engine bolt to the body for a better grounding of the engine/alternator. Still get the light.
Today, I plan on picking up a 1 amp diode to increase the alternator output as suggested by ZZP in their tech articles. I could buy their Stage 1 alternator rewire, but I can solder, so I'll save my $15 and do it myself. Hope this works.
So where should I turn next? As I said, the car starts, runs, and drives just fine. Just the annoying light comes on. What else can I check or do?
