On friday afternoon I notice a sound (kind of like a bird) coming from under the hood. It increased with RPMs so I think it was one of the belt driven accessories on the engine. The next time I got in the car (yesterday afternoon) the battery light was on so I thought it had to be the alternator. I drove it up to the oreilly store to have it tested on the way there the windows were going down slower than normal and the turn signals were slower also.Before the guy did the test he said the negative cables were a little loose in the terminal and he tightened them. I started the car and the battery light was off and all electrics were working normally.So my questions are,will a loose ground wire cause the battery light to come on and if a alternator when going bad will it work sometimes and other times not? I always thought a alternator either worked or it didn't. I am just trying to reassure myself that the ground wire was the problem.

 

Well this morning I got in the car and after running about a minute the battery light comes on again. I drive to the parts store and as soon as I pull in the parking lot the light goes off. Then on the way home it came on again for a few seconds and went back off. The battery is brand new so I know its not the problem. The guy load tested it yesterday and said it showed 100%. Could it be the alternator is working sometimes and other times not? I checked all the wires and they are all tight. I do not have $132. to waste on a alternator if that is not my problem. Every time I go somewhere to have it tested the light goes off and it shows its charging. Need some advice.

 

Weird sound under the hood and intermittent battery lights, check your alternator belt for condition and tightness. While you are it, check your battery condition and wiring for caking and cleanliness. Get a cheap voltmeter on both the battery and alternator to see their condition.

 

Battery is good,terminals and wires are good and the belt is tight. Its weird, I havn't heard the chirping sound except for last friday. Its sounded like maybe the bearings going bad in something. I thought that a alternator either worked or it didn't. Never heard of one that worked intermmittently.

 

Well it turned out to be the alternator was going bad and finally went this afternoon 4 days and 200 miles after the first symptoms occurred. Today they tested it on the car with the car running and the light on and it tested that it was charging. I came home pulled it off and had it bench tested and it showed it only charging 10.8 volts. Put a new one and problem solved.

 

Well it turned out to be the alternator was going bad and finally went this afternoon 4 days and 200 miles after the first symptoms occurred.