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Category: Chevy
Satisfied Customers: 26591
Experience:  ASE certified tech ADVANCED LEVEL SPECIALIST. Wisconsin certified emissions state inspector
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2002 Chevy Cavalier: trouble with the charging/electrical system

Customer Question

I have a 2002 Chevy Cavalier. I'm having trouble with the charging/electrical system. I originally started having problems and it was only with the battery dying. So, I bought a new battery and that did not fix it. I bought a new alternator, changed it, still no good. Took that alternator back, tried another one and that was also not the fix. Between changing the alternators, I started to notice random lights turning on in the dash. Now, while driving, the lights on the dash will take turns coming off and on. Sometimes the gauges will get all messed up and the tachometer will actually say error on it. I'm not sure what to look at next. Can anyone help me?
Submitted: 8 years ago.
Category: Chevy
Expert:  AMEDEE replied 8 years ago.

Hello there!


WHat lights are illuminating on the dash or instrument cluster?


Are there any codes in the computer?


Does your vehicle die or stall on you when driving?

Customer: replied 8 years ago.
all of the lights illuminate. It normally starts with the theft system light, check engine light on the left side and then about 30 seconds later all of the lights will come on approx. 20 and the temperature gauge will fall to zero. They nomally all stay on for about 30 seconds and then will go back out. When they all come on, the odometer will say error on it. The car runs fine once its started other than the lights on the dash turning off and on. I had the car to Advanced to check it with their computer and it says that there are no codes. They tested the charging system and said that it seems to be charging fine adn that there is no power being drawn when the car is off. If I charge the battery, I can normally drive it for a few days until it eventually goes dead. If I leave the car sit for a few days, the battery stays charged.
Expert:  AMEDEE replied 8 years ago.
SO when this happens, the alternator is charging the battery...correct?
Customer: replied 8 years ago.

According to the testing machine at Advanced, yes it is charging. I'm assuming that it is not charging as much as it is drawing though because I can drive it for awhile, the car will run fine, as soon as I shut it off, the battery is dead. It never goes completely dead, just dead enough to not allow it to turn over the vehicle.

Expert:  AMEDEE replied 8 years ago.

WOW! Ok... It sounds like you definitely have a electrical gremlin.


What we need ot do is find out for sure if the alternator is charging or not when this problem happens. If you were to take voltmeter and put it on your battery when this problem happens, we need to see a minimum of 13.8 volts. If there is anything less, we simple have a charging system issue. If the alternator has been replaced, we could be missing an input to the alternator causing a no start condition.


If the alternator is charging when this is happing, then we simple do not have a charging system problem going on, just a electrical issue we need to address.

Customer: replied 8 years ago.
ok, What exactly do youmean by "missing an input to the alternator"? I'm not exactly sure how I'm going to test the voltage when its doing it because it only seems to do it while driving. Do you have any other suggestions? Do you think it could be a computer problem? How do you recommend chasing an electrical issue?
Expert:  AMEDEE replied 8 years ago.

Well, if this were me working on it, I would plug in a scan tool and watch the computer parameters while this happens.


If you do not have access to a scanner, I would drive it around until it acts up then just pull over, pop the hood and check battery voltage.

Customer: replied 8 years ago.
ok, if it is low, then what do I look to next? If it is adequately charging, where do I look to for the electrical gremlin?
Expert:  AMEDEE replied 8 years ago.

If the battery voltage is low when this happens, then we will need to check the inputs to the alternator. There is one plug and one big wire to the back to the alternator. Be sure that the big wire and that the wires in the plug that go to the back of the alternator have battery voltage to them.


If the battery voltage is not low, then we will need to starter checking the instrument cluster, and the other modules on the vehicle to diagnose this problem.

AMEDEE and other Chevy Specialists are ready to help you
Customer: replied 7 years ago.

Sorry I've taken so long to get back to you. I lost my internet for a week and was unable to reply. However, since I talked to you last, I have checked both wires on the alternator and have taken my car to a garage to have it tested. I used all the information you helped me with and explained to them what was going on. They hooked it up to their computer and couldnt get it to give them any consistent codes. They checked the voltage from the alternator and said it was good also. I'm going to accept your answer and begin to look into the instrument cluster and other modules. Do you have any suggestions on where to start looking? They told me at the garage that they'd have countless hours chasing down the problem and that the best bet is to run the car and see if you can figure it out while driving it.

Thanks for you help. Any other information you have will be greatly appreciated.

Expert:  AMEDEE replied 7 years ago.

Thanks for the accept!


Let me ask you this... Do you have a voltmeter gauge on your dash or instrument cluster?

Customer: replied 7 years ago.
No, unfortunately I do not
Expert:  AMEDEE replied 7 years ago.

Sorry for the delay!




We are going to have get a voltmeter on the battery and watch the charging system voltage when this happens. If the battery voltage drops below 13.5 volts while the engine is running, the alternator is not charging. I would be willing to bet this is due to a missing alternator input.

Customer: replied 6 years ago.

I ended up having to take this issue to a local garage. They found that the alternator had a poor ground and then ran a jump wire from the battery to the alternator. The car has run good since.



Expert:  AMEDEE replied 6 years ago.

Glad to hear it is running good!

Have a great day!