what do you do to diagnose the alternator......or to tell if it is bad never had a bad one so i dont know what to look for.

 

Start the car and disconnect the negative battery cable. If the car still runs your alternator is OK. What makes you think the alternator is bad?

 

i had the battery checked at autozone and checkers, they said the battery was good so i replaced the alternator, no more dying car.

 

some one said could be bad alternator??? i was at light it just died??? no reason i didnt stall or anything

 

I think if your alternator was bad you would see your lights start to flicker ect. Stalling out can be a bunch of problems but you still might want to do Rated R1's test, never hurts to check.

 

7-sins is right, if it has something to do with the electrical system (battery, alternator) the ligts should dime and the car should dye sorry for not stating that earlier

 

Does anyone know a good way to tell if the alternator is on its way out? Not dead completely, but you know, on its last legs.

 

exactly what lost time says i wanna know if you can tell if its on its way out when i hit brakes lights interior dim a bit cant really notice but it does dim and also when i have radio up loud

 

Go to PepBoys or similar and have them check your alternator. They will do it for free.

 

rynberg, what are they checking? Is it just output of the alternator?

 

NTB will check the whole system while its running with a computer diagnosic. 10 bucks and it tests Battery, Alternator, Voltage regulator, starter etc. Gives you a print out and will show if your alternator has any burned out diodes. Most have 3 diodes and if 1 or 2 die the alternator will work but will put out much less AMPerage. Have it checked on a computer diagnostic. 10 bucks is cheaper than just replaceing 200 dollar alternator or a 70 dollar battery.

 

Sorry, who is NTB?

 

National Tire and Battery, NTB.

 

The altenator warning lamp should illuminate when it goes bad. Misfiring can happen.

Isn't there a way to measure output with a multimeter?

Make sure your battery terminals are clean too.

 

Yeah NTB. Thier computer will test the system under Load. Thats how you can determine how much power its producing and it will give a read out.