The reason I need to know is because my batt died while I was driving the car, couldn't go over 60 mph with the lights on, car was lunging forward and not shifting properly (automatic). I found that my acc/alt belt was slipping drastically. I fixed it and had my batt charged and checked at AutoZone, they said it was still good. I tried starting the car then disconnecting the negative cable from the battery and the car continued to run but died as soon as I turned the lights on. Is that a proper way to tell if the alt is working? thanks

Also, I'm not getting any batt/atl or emergency brake lights coming on at all like I did when my belt tensioner first came off and left the alt not spinning at all.

 

Autozone can test your alt too.

 

get a voltmeter...at idle the voltage should real 13.XX to 14.4.
anything that's close to 12volts at idle usually means your alt is dead or going to be.

 

okay, i did the voltmeter test last night after I got home and with the car off, my batt read 13.23 volts. 14.01 with the car on. Does this mean my alt is in good working condition?

 

Do you have a 98? You may be part of the alternator recall. You may be able to get a new one for free if you are. The recall is because it can catch fire, not because it just stops working, but if you can get it replaced for free, why not. When I took mine in, they didn't even examine it, I told them I got a recall notice and they said they were just going to replace it, and they did.

 

naw, mine is a 95. thx for the info about the recall though.

 

HAynes manual : a voltmeter at a good battery posts, when engine not running, should read 12.5 Volts, When engine is running: should read between 13 and 14 volts, above 15 Volts is no better.

 

my car stalled on me to while i was driving and i thought it was the alternator.but it was from the batter terminals haveing to much corrosion on them.so just make sure they are clean.

 

when the alternater is going it usually makes a whining noise. mine did when it was dead, and its a b**** to do yourself. it took me a few hours to do.

 

i just changed my alternator a half a year ago...but just recently i've been hearing a whining noise coming from out of my back speakers....is it going dead? what are other symptoms?

 

You are hearing alternator whine. This is usually heard through speakers.

An alt. doesn't have to whine to indicate if its going or not.

 

It is probably just distortion, they sell filters for that. It will filter out the engine noise.

 

Getting a filter is only a bandaid to the problem for the whine in your speakers. When you hear alternator whine from the engine bay, then it's a sure sign that your alternator is about to go. If you hear alternator whine from your speakers, that's a wiring issue. It's caused by power wires sitting next to the wires that carry your audio signal. I'm guessing you have an aftermarket setup in your car? The general rule is to run the power wires for your amp in the trunk down one side of the car, and then run the RCAs for the amp down the other side.

DW

 

My first assumption! you are the man. Thank you.

 

Bmr4life:

An at home load test is what you need to do. With your engine on, turn on your AC with fan speed at 4, headlamps (foglamps too) and your rear window defroster. The voltage at your battery terminals should NOT drop below 12.5 volts.

When my voltage regulator in my alternator went, the voltage dropped to less than 10 before I got scared and turned everything off.