I stopped at traffic light and my car went off and won’t start again. I had it towed home, it will jump start and keep on running as long as the jump start pack stays connected. As soon as i disconnect the jumpstarter it shuts off. There are no warning lights on the dash while engine is running. My guess is alternator is bad and car ran on battery till battery was discharged and the it stopped on the road. Now if this was the case shouldn’t there be a battery and/or break warning light on the dash while car is running on battery?
Also if it were a battery problem then the car should run on power from the alternator once it’s jump started right? In which case there should be a battery warning light on the dash right? I know the dash lights aren’t bad because when i turn the key to the on position all the lights show up, including the battery light. I will like to take out the alternator and bring it the the shop for testing but before doing this i’ll like some input since i’m not very convinced it’s the alternator because there’s no battery signal on the dash while engine is running on battery.
Hook a voltmeter up to the battery terminals with the engine idling.
Ballpark figures are 13.5 - 15 volts. 14 volts is an acceptable value for most vehicles.
It is important that the battery warning light works since most vehicles use that circuit to supply current through the lamp to the exciter field of the alternator. You say it turns on during the test mode so that checks good. Check the fuses in the dash and under the hood and see if there any blown there. Make sure the battery connections are clean and snug to the battery posts and the main alternator output lead is making good connection with no signs of burning. If all those things are good then the alternator may be bad. Checking the voltage on the main output lead, it should be around 14.5 volts while the engine is running around 1500 RPM. Have the battery checked also to make sure it is in good condition. It is a good idea to replace the alternator and the battery at the same time if the battery is marginal and the alternator is defective.
When you are hooked up to something else providing power to the battery, the alternator warning light might not come on. This is because that light is in series with the power from the alternator, and the circuitry would assume no power is needed from the alternator because the battery is getting its power from the jumpstarter. I guess the first thing I’d do if this were my car, and I suspected the alternator was broke, is charge up the battery overnight with a battery charger, then see if it started and ran ok. A car will run with a bad alternator for some time, with a fully charged battery it can take an hour or more before the battery becomes so discharged the car stops.
Thanks Db4690, Couger and GeorgeSanJose for your suggestions. I pulled out the battery and had it charged at Autozone today for an hour. With the ignition off the digital voltmeter reads 12.45V. With the ignition on and engine running, the Voltmeter reads 12.17V across the battery. So it looks like there’s no charge coming from the alternator.
I assume if this is a belt problem then there should still be at least some current from the alternator, so most likely the alternator is bad or there is a circuit problem somewhere. Alternatore fuse in fusebox close to the battery on the driver’s side is not blown. I couldn’t access the other fuses in the fusebox on the passenger’side. Is there like any charging relay i could check before taking the car to the shop to have the alternator replaced?
So there was only 12.17v across the fully charged battery at idle?
In my experience, belts are rarely the source of charging problems, unless they’re very loose, in which case you may have a problem with your automatic tensioner, if the engine’s so equipped.
To me, it sounds as if your alternator quit.
Most retail auto parts store – like Auto Zone – have a test gadget that will test alternators. They’ll usualy test them for free. Suggest to ask if they do. Depending on how they do it, it may or may not have to be removed from the car first.
Thanks once more Db4690, Couger and GeorgeSanJose for your help. I ordered an aftermarket alternator online for $128, installed it today and car now runs fine. Voltmeter reads 14.6V with engine running after installation. I’m still puzzled as to why there was no warning light when alternator died and car was running on battery power before stopping on the road after battery was drained, especially since the light is there when i turn the key to the ACC position without starting indicating that the warning circuit was ok.
im having the same issue and cant get a straight answer is there an inline fuse for the alternator and any usual connectons to check for issues or if my alternator is just bad that its about the same specs for this posts
Assuming you are in the US Autozone will check your alternator and battery for free. And you did not need to drag up a 6 year old thread to find that out.
Please start your own like you did with your other questions.
Hey My car is driving so good but it seem like if I go a long drive & it’s to far it cuts off when it cuts off if can be in the middle of the road at a light anywhere when it cuts off the battery light come on & Alternator light I keep pushing the gas it doesn’t move at all sometimes I have to cut car off leave it off for 5/7 mins & sometimes when I crank it back up it shoot back working or sometimes and the middle of the road when it cuts off I keep pushing the gas and the car tryna to right but still cut off & sometimes it just shoots off letting my car fly & bsck to driving regular my mechanic at first said my alternator look brand new and I don’t need one and now I just got everything fix on my car tune up in everything & it’s driving so smooth but still when I go far it’s cuts off and battery light and alternator light come on what do this sound like please help so confused
You should really have started a new thread post for this issue.
I suspect that the trouble you are having is caused by a problem with the ignition system. A bad connection perhaps, is heating up and causing a voltage drop to happen which in turn robs power from getting to the ignition system. It could be something else in the ignition system also. Once the engine stops running and the ignition is ON, the alternator warning light will turn on also. That is normal operation for that. If the trouble isn’t with the ignition system then I would check for a fuel delivery problem.