low battery lights surging

[certainsider]

I have recently given my son my beatiful 1992 Q45 which i have owned for 14 years. As i handed over the keys and our first drive the low battery charge warning is displayed and then OK; repeating again and again.I had replaced the alternator in 07 and replaced the battery as well in 07; and only have 3 thousand miles since they have been replaced with new parts.I have had the battery tested and the alternator tested to find they are perfect. i reinstalled items assuming something was loose and checked wire harness; fuses, and ground wires and all seems well.i have searched for answers on this and other sites along with asking my mechanic and have not resolved it yet. does anyone here have a suggestion?your help would be great.

[3Q Jay]

genuine -60u02(r) alternator?unless your idle is below 400 rpm, then the problem is either your alternator, and/or battery. 3 years is 30 years to a conventional battery if not properly maintained.

[certainsider]

thank you for your response, it is a nissan alternator which output 14.7 volts.i was just going to get a new battery just to see if that could be the problem. does the computer control the charging system?

[qship96]

Agree, the G50 has PROVEN to destroy brand new quality batteries in 36 months- over and over. Start with a fresh, high quality battery and re-evaluate. Even if it does not solve the issue, it is needed anyway.

[certainsider]

a new battery did not cure the low charge message.should i just replace the wire harness or the alternator even though they have been tested good?thanks

[MinisterofDOOM]

Bad alternators can be hard to "catch." My Maxima ate alternators on a regular basis and every time, without fail, the bad alternators would test good. It would often take multiple tests to catch it in the act of failure in order to convince the retailer that I needed a replacement under warranty. Load tests (requiring removal of the alternator from the car) are more accurate than idle tests on the car; but the way I see it if you're going to the trouble of removing the damn thing, you don't want to put it BACK if it's questionable, even if it tests good.

[Infinitiguy19]

No one mentioned to look in the service manual to see if the Diagnostic Display screen is faulty?

http://picasaweb.google.com/lh...tlink

Is the brake light on at all?

Are there any other lights on that are not normally lit (TCS OFF, SLIP, ABS)?

[certainsider]

thank you paul for your comment and to be honest i did read this and do not understand the A diagram and have no idea how to attempt the second one as i am sure you know there is no room to get to the L cable when it is installed. I forgot to go back to this.i will certainly give it a closer look and figure it out tomorrow.

thanks again.

[Infinitiguy19]

The "A" Diagram is simple all your doing is grounding the pin for the alternator message. "M47" is the connector for the diagnostic display. Now getting to it is not easy but that will rule that out IF the alternator and battery are NEW.

Pin #1 is groundPin #13 is the alternator message

What brand alternator did you use?

The "B" diagram is just checking to see that the alternator puts out more than 8 Volts because anything under will trigger the "Low Battery Charge" Message.

[certainsider]

it is hard to get at for sure, but i have done it so many times in the past 2 weeks i can do it with my eyes closed now.I would preffer not to be so good at this but it is hundred time easier than the starter!Thanks for the info; i was wondering which was better to test in the car or out! have had it done both ways tho.

[Infinitiguy19]

You mean you have taken out the instrument cluster or the alternator because I am talking about the instrument cluster.

I am not sure whats a better way of testing the alternator because it may be about the same (in or out of the car). Also make sure that belt is tight other wise a loose alternator belt can cause low voltage problems and more.

[certainsider]

I know the alternator says NISSAN on the back and i honestly believe i purchased it at dealer because thet are the only ones which has them within 5 days around here.I can look and post tomorrow as there is a sticker on the back of it too.

[certainsider]

Paul i failed to mention the brake light comes on very faintly and then goes out. the red e brake light in lower right hand dash.is this just from having low charge on battery?

[Infinitiguy19]

Paul i failed to mention the brake light comes on very faintly and then goes out. the red e brake light in lower right hand dash.is this just from having low charge on battery?

Thats good on one hand but that also makes it harder to diagnose because if it was a crappy rebuild then we can put the fault on it. But since its a good OEM Nissan Rebuild that makes things a littler harder.

Paul i failed to mention the brake light comes on very faintly and then goes out. the red e brake light in lower right hand dash.is this just from having low charge on battery?

Yeah that means there is a problem with the alternator but I haven't heard of Nissan OEM alternators failing so fast. Was the alternator trying to charger a dead battery or something?

[certainsider]

paul you are are good man with all your help! thank you!I had replace the battery at the same time as the alternator cause it was older and seeing how i was under the hood anyway i did both.The car did just sit for some time and had to jump it when my son and i started getting it ready for him.I have been driving it on semi regular basis from August till Thanksgiving and had no troubles at all. It then stood still till my birthday when i took it out of the garage and the Low Battery Charge message appeared and i simply wrote it off as from sitting; after a drive the message dissappeared for a day and then everything everything crashed as we drove home with the radio and heat turned off with just running lights in the dark.Very similar to the last time the alternator went bad; just could not believe it as these parts last so long. my first thought was I bought a cheap battery but it is not; top line titanium.i plan on trying to figure out the diagram and if that doesnt work i will give in and bring it to the dealer. This was something I wanted to figure out on my own but my boy is loosing out so i need to get it done.thanks very much, and hope i can return the help someday!

[Infinitiguy19]

I am happy to help because I am just returning the favor to NICO for putting up with my crap.

There are some tests that can be done to confirm the health such as a battery load test which can be done at Advance Auto for free: http://www.batterystuff.com/tutorial_battery.html

And you can also do multiple checks one the alternator while its in the car still: http://www.aa1car.com/library/charging_checks.htm.

Good Luck

[certainsider]

Paul thank you again for all your help.I found a BOSCH alternator at PEP Boys for $160.00 and I bought even tho the NISSAN one tested on the bench as good again and the problem is solved!I can not believe the alternator tested fine twice yet it was the cause of all this trouble.If you ever have a question about siding or about anything pertaining to your home I am here for you. [email protected]