My Daughter called and said her car was dying. Someone would give her a jump and after a few minutes the lights would dim and car would quit. When I got there I basically did the same, jumped the car, and sure enough shortly after you pulled the cables off the lights started dimming, engine started running rough etc. I did not notice before the lights diming the battery light or e-brake light on.

Took the battery out, gave it a full charge, the battery tested fine at AZ. Stuck it in the car drove home (4 miles). At no time did the battery light or e-brake light come on. Put a Volt meter on the battery, car not running, 12 volts, started car, reved engine battery volts 12 volts, did not move once started. still no battery e-brake/light.

Tommorow I plan on starting the car and pulling off a battery ground cable to see what it will do. Will that screw up the voltage regulator?

To me sounds like alternator, any suggestions?

 

It wouldnt hurt to pull the grounds and clean them.
It sounds like the alternator to me. Have you checked the tension on the belt? How old is the current alternator?

 

Sounds like whats been happening to me lately too, except my brake/batt light have been on more than not.

Check the grounds on the alternator first and make sure the belt is tensioned properly, as said above.

And AZ will test your alternator while its still on the car...they basically hook up a volt meter to the battery it gives them a readout of the voltage the alternator is putting out. Might be worth a shot.

 

Sounds like a bad alternator. Should be getting 13.5-15V while the car is running. Double check belt tension and all the connections.

 

no batt light? with only 12V while running you should get a battery light. charging voltage is 14V as dizzle said.

putting that aside for a moment, your symptoms are certainly a bad alternator. have it tested in-vehicle at a shop. they will look for 2 things: proper voltage level (which you already fail) and ripple voltage. the alt actually produces alternating current. the rectifier changes it to DC but some ripple voltage will always be present. if therre is no ripple then your rectifier (part of the regulator) is bad. replace the altenator.

warning!! - do not install an aftermarket alternator! insist on an OEM Nissan part. any shop should be able to get one from the dealer. or just go to the dealer. aftermarket altenators are junk. do a search and you will see.

back to the batt light - i'd say a bad ground could be causing 12V at the battery while the alt is putting out 14V, but then your car wouldn't start. not sure what to tell you about that.

 

I would not pull off the battery ground with the car is running. This causes a condition called "load dump" where voltage can spike as high as 120 volts or so across the electrical system. This is the single most difficult condition for an automotive electrical system to deal with. However, this assumes that the alternator is charging the battery.

You can try cleaning the grounds and tensioning the belt as stated above, but your alternator is probably bad. Depending on the mode of failure, the brake and battery lights do not always come on.

 

did you measure the voltage at the alternator? try that and see what voltage you get.

 

Another thing to do if you have a DMM is to set it to 20V scale on DC volts and put the red lead on your output terminal on the alternator itself and ground the black lead. If you are getting charging voltage, you've narrowed it down between the battery and the battery cables. If not, replace the alternator.

Auto Zone, O'Reilly's, Pep Boys, etc. all sell alternators with limited one year or lifetime warranties depending on how much you want to spend.

Good luck.

 

Thanks everyone

To answer some of the questions, the car is a 1999 with 150K on the clock. orginal alt.

I will check grounds.

nd I don't trust rebuilt alternators, so I always get the lifetime warranty or an OEM.

I will check voltages at the alternator and not pull a battery cable off with engine running.
(follow up, no difference in the voltage at alternator, reving engine up doesnot change the voltage either)


I don't know why the battery light and e-brake lights are not comming on???

Again thanks