Alternator overcharging?
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Teching In
Joined: Jul 2014
Posts: 3
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Alternator overcharging? My 99 LS1 seems to be overcharging. Alternator is just a year old, could it be anything besides that? Battery gauge bounces from normal to in the red, idiot lights all flash like they're on a Christmas tree.
UPDATE: I had the alternator replaced. It's still doing the same thing with the dash gauges and all, but it's added a twist.... we were driving it on the Interstate when it started acting up again. This time, in addition to the dash lights and all, the car sounded like we dropped it into 2nd gear and the rpms went up to about 5000. When we let off the gas and slowed down to about 45 mph, everything seemed to go back to normal. When we tried to accelerate again it started acting up again. We also had the headlights on and they were going bright and dim. We limped it home and parked it. I am going to buy a new battery for it, Im just hoping it's not the brain or something like that.
UPDATE: I had the alternator replaced. It's still doing the same thing with the dash gauges and all, but it's added a twist.... we were driving it on the Interstate when it started acting up again. This time, in addition to the dash lights and all, the car sounded like we dropped it into 2nd gear and the rpms went up to about 5000. When we let off the gas and slowed down to about 45 mph, everything seemed to go back to normal. When we tried to accelerate again it started acting up again. We also had the headlights on and they were going bright and dim. We limped it home and parked it. I am going to buy a new battery for it, Im just hoping it's not the brain or something like that.
TECH Fanatic
Joined: Dec 2017
Posts: 1,467
Likes: 265
From: Bossier City, Louisiana
Do you have a good multimeter? Set it to whatever is close to 20 volts DC and put the red pin onto the battery positive terminal and the black pin onto the negative post. Start the vehicle. What do you get for a DC voltage?
Flip the **** to a reasonably high AC volts setting. Still, with the engine running, what do you see for AC volts at the battery? It should be a vanishingly low value for AC volts. Think way, way less than a tenth of a single volt here.
Rick
Flip the **** to a reasonably high AC volts setting. Still, with the engine running, what do you see for AC volts at the battery? It should be a vanishingly low value for AC volts. Think way, way less than a tenth of a single volt here.
Rick
