1994 Nissan sentra Charging problem.

[mikall33]

I have a 1994 nissan sentra that has had a new alternator put on 2 times and battery is new. The alternator is failing to charge my battery. After a long rest it starts up, alternator is putting out 14.4 volts or so. All the lights on the gauge cluster light up as they are suppose to when I turn the key on just before i start it. (meaning the battery indicator, brake indicator, check engine and door light). and then it runs fine. sometime between 5 and 10 minutes after everthing is warmed up... My alternator stops charging, dash lights go dim. windows and wipers are slow. I have done voltage testing on it at the battery. For a few seconds the battery voltage reads about 13 and then continuously decreases until there is not enuff power for the car to run because the alternator has stopped charging. At the point the ALTERNATOR stops charging, if i turn off the car and then turn the key to ON position, the battery indicator light and the brake indicator light on the gauge cluster WILL NOT come on. When the alternator is pushing 14+ volts.. those lights will work. I know that the battery light is slaved by the brake light and that that light is in the circuit between the ignition switch and the alternator. I understand how that works. however when the alternator is not charging, those lights cease to work. I have changed the ignition switch. didnt fix it, i had the alternator checked ON and OFF of the car. tests fine. it seems everytime i take it somewhere, and they test it. they tell me all is fine and send me on my way only to be stranded 20 minutes later on the road. im at my wits end. even nissan told me nothing was wrong. any information would help. is there a way i can use my multimeter to test the grounds on the car? the one from the negative battery cable to the chasis tests fine using the continuity tester, and from the alternator to the motor. I dont know if i should test resistance on the grounds or even how to do that. all I know is i can see on the volt meter at the point it stops pushing out 14.4 volts and plummets to 12.9 and then keeps going down and down and down.. I have changed all the obvious but still giving me grief. Thanks in advance for your help.
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[RED_DET]

I would recommend adding new ground wires instead of trying to check what is there.

The next obvious that you didn't mention checking was the battery itself. I would also have that tested, I had this culprit on my wifes old 2002 Nissan Sentra.

[PapaSmurf2k3]

+1 for putting new grounds on. I'd also check all the connections to your alternator for corrosion. Its also possible there's a relay somewhere that just quits working once it gets hot (maybe?)

[otto888man]

Where did you get the alternator? I have seen alternators been replaced so many time from the same parts store or the same supplier & it turns out that they installed substandard components & starts failing as soon as you installed it. Even the owner took it to the parts store & test bench it. It turned out to be bad batch of alternators.

[otto888man]

Keep us posted.

[Asiangem]

I realize that this is an old post -- but for those who may still have the charging problem for the battery my friend just went through this problem and got his car fixed -- My friend is a Honda Vehicle Technician who owns a 1994 Nissan Sentra which had kept dying on him. He had called the AAA driver who stated that the alternator was good as noted on the print out report when the AAA driver ran the check on the system. It turned the alternator was bad, which somehow also affected the starter. While the AAA driver had jump started the car, the ignition switch relay got broken; and the small positive cable connection got a short; so it all, he replaced the alternator, the starter, the battery and got a new battery cable connectors, ignition switch relay and fuse for the inside of the interior lights -- and he has no problems since after spending 4 days on this problem. It would had been easier had he had a lift and the right equipment but nevertheless he got it done but missed his work -- but at least its fixed.