rob487

Hi. I'm new to the forums. I just bought a 2000 Cavalier w/ the 2.2L in it, and it's been a rather frustrating car. I knew it had problems when I bought it, so I got myself into this situation. My problem is that the alternator isn't getting any juice to the battery. I thought it was bad, so I went and bought a new one. Same problem. I had it tested and the alternator itself is fine. But with the car running, the battery only reads around 11.60 volts and the battery light comes on. I did notice there is a ground wire down by the starter that is unhooked, but it seems to make no difference w/ it hooked up or unhooked, but maybe you could tell me where it SHOULD go? There are three wires down by the starter. The positive is hooked to the starter w/ a 13mm nut, then there's a little tiny ground hooked to the starter w/ a tiny 5/16" nut. Where does the third wire go? It appears to be a ground... it's the same size as the positive that's hooked to the starter, but the wire is almost a blueish in color. (Like a very faded black ) Any ideas on where that should go, or any pointers on what to check next?

mobil_12

check your charging voltage at the back of the alternator where the main wire hooks up and to battery ground. If you have charging voltage there, then you have a bad wire betweent the alt and battery. If you only have 11.8v there then check to see if the signal wire to the alt has power. If it does, and there is no charging voltage out of the alt, then the alt is bad. If there is no voltage from the signal wire, then get a wiring diagram and find out where it comes from. Keep it simple and start with fuses.

rob487

Ok, I've done some tests. The signal wire has power, so that's not the problem. Testing the circuit between the alternator main wire and battery ground shows only 0.08 volts at idle. When revving the motor, it shows only 0.35 volts max. So I guess the alternator is bad. Also, I noticed sometimes when I shut off the car, the warning lights won't turn off. They only go off upon disconnecting the signal wire from the alternator.

Anyway, Advance Auto Parts tested the alternator and their machine showed 16 volts of charging power. Why would their machine say it's good, but yet my tests clearly show it's not?

deadBird

The wire is bad.

rob487

Yep. I traced the wire around the engine bay and it was kinked. I replaced it and it works good now. Thanks!