alternator not charging
12-01-2004, 06:27 PM
#1
Senior Member
Thread Starter
Join Date: Aug 2002
Posts: 196
alternator not charging
I'm not really familiar with the electronics on these cars, but a friend has one that's having problems. It seems that the alternator isn't charging the battery. He just got a rebuilt one from a parts store, and it's giving problems just like the old one did. He took it back off the car, and the store tested it again and it showed good...it just doesn't work on the car.
He cleaned and checked all connections and still no change. I'm thinking a fusible link or something is preventing it from working properly. I will likely be going tomorrow to help him on this car. Any suggestions on which fusible link, where it is, or any other ideas will be appreciated.
thanks.
He cleaned and checked all connections and still no change. I'm thinking a fusible link or something is preventing it from working properly. I will likely be going tomorrow to help him on this car. Any suggestions on which fusible link, where it is, or any other ideas will be appreciated.
thanks.
12-01-2004, 07:31 PM
#3
Senior Member
Thread Starter
Join Date: Aug 2002
Posts: 196
He bought the battery new recently, and it's good.
His volt meter shows about 11.5V, and after he starts the engine, it will go up slightly but not even to 12. These numbers were after the car had been driven, which explains not having a full charge with the key off...since the car had been ran on the battery power for a little bit since it was charged.
The fusible link...which one is it? Is it just a wire type that can be checked for continuity?
I know these questions sound really ignorant, but I've not looked at the car and want to be able to go right to the problem without having to spend forever just finding the location of things.
His volt meter shows about 11.5V, and after he starts the engine, it will go up slightly but not even to 12. These numbers were after the car had been driven, which explains not having a full charge with the key off...since the car had been ran on the battery power for a little bit since it was charged.
The fusible link...which one is it? Is it just a wire type that can be checked for continuity?
I know these questions sound really ignorant, but I've not looked at the car and want to be able to go right to the problem without having to spend forever just finding the location of things.
12-02-2004, 08:48 AM
#4
Senior Member
Join Date: Nov 2002
Posts: 548
I've had some problems with alternators in my maxima and sentra. here's a couple quick checks.
in order to get power from an alternator, you need to put power into an alternator. this is done through the two-wire connector. the thicker wire is the sense wire, which is connected to the battery. the voltage regulator uses the voltage from the sense wire to determine the battery's charge level and alternator output, and controls the alternator from that. with no input from the sense lead, the alternator will not work. the thin wire is connected to the diode trio inside the alternator and goes to the charge indicator light on the dash to warn when the alternator is not producing current. with the engine off and the ignition on, battery power goes through the charge indicator light and energizes the alternator's electromagnetic field to produce power. when the engine starts, the power generated from the alternator is then used to power the alternator's field. since that input circuit is no longer being used, the warning light goes out. if the alternator doesn't produce current, the input circuit is still energizing the alternator's field circuit. with current still flowing through the indicator light circuit, it comes on. however, do not rely solely on that light to inform you of a problem.
before you start anything, check the fuse in the fuse panel that says "meter". if it's blown, the gauges will not work. that fuse also energizes the alternator field through the warning light. so the fuse must be good.
(1) turn the ignition switch ON, you'll hear the chime - but don't start the engine. your charge indicator light - the very first light on that strip on the dashboard, looks like a battery - it should be ON with the engine not running. that means the input and field circuits are OK. then start the engine - it should turn OFF.
if that doesn't light up during the initial check, you've got an open field circuit which will prevent the alternator from working. a bad regulator, bad armature, or worn-out brushes in the alternator will cause that. if the charge indicator light stays on when the engine is running, chances are the diode trio is shot.
(2) now start the engine. with a digital voltmeter, measure the voltage across the battery terminals. red is positive (+) and black is ground (-). 14.4 volts is ideal, but anywhere between 13.8 and 15 is acceptable. If it's less, leave the negative probe connected to the battery's ground terminal and touch the red lead to the lug at the back of the alternator. if voltage here is between 13.8 and 15, there's a broken connection between that thick wire and the battery. if voltage is below 13.8, there's still a problem.
(3) with the engine still running, connect the voltmeter back to the battery. in the car, with the engine in park or neutral, slowly rev the engine up past 3k a couple times. If the lights suddenly get brigher and the voltage shoots up, there's an open sense circuit going to the alternator.
(4) if you've still had no luck, shut the engine off and double check your connections at the back of the alternator. there should be that 2-wire gray connector, the thick wires connected to the big screw terminal, and some thin ground wires connected to the alternator's frame. make sure the connections are clean and not corroded or oxidized. clean them off, then try it again.
there's more, but try these and let us know what you find.
Dan
in order to get power from an alternator, you need to put power into an alternator. this is done through the two-wire connector. the thicker wire is the sense wire, which is connected to the battery. the voltage regulator uses the voltage from the sense wire to determine the battery's charge level and alternator output, and controls the alternator from that. with no input from the sense lead, the alternator will not work. the thin wire is connected to the diode trio inside the alternator and goes to the charge indicator light on the dash to warn when the alternator is not producing current. with the engine off and the ignition on, battery power goes through the charge indicator light and energizes the alternator's electromagnetic field to produce power. when the engine starts, the power generated from the alternator is then used to power the alternator's field. since that input circuit is no longer being used, the warning light goes out. if the alternator doesn't produce current, the input circuit is still energizing the alternator's field circuit. with current still flowing through the indicator light circuit, it comes on. however, do not rely solely on that light to inform you of a problem.
before you start anything, check the fuse in the fuse panel that says "meter". if it's blown, the gauges will not work. that fuse also energizes the alternator field through the warning light. so the fuse must be good.
(1) turn the ignition switch ON, you'll hear the chime - but don't start the engine. your charge indicator light - the very first light on that strip on the dashboard, looks like a battery - it should be ON with the engine not running. that means the input and field circuits are OK. then start the engine - it should turn OFF.
if that doesn't light up during the initial check, you've got an open field circuit which will prevent the alternator from working. a bad regulator, bad armature, or worn-out brushes in the alternator will cause that. if the charge indicator light stays on when the engine is running, chances are the diode trio is shot.
(2) now start the engine. with a digital voltmeter, measure the voltage across the battery terminals. red is positive (+) and black is ground (-). 14.4 volts is ideal, but anywhere between 13.8 and 15 is acceptable. If it's less, leave the negative probe connected to the battery's ground terminal and touch the red lead to the lug at the back of the alternator. if voltage here is between 13.8 and 15, there's a broken connection between that thick wire and the battery. if voltage is below 13.8, there's still a problem.
(3) with the engine still running, connect the voltmeter back to the battery. in the car, with the engine in park or neutral, slowly rev the engine up past 3k a couple times. If the lights suddenly get brigher and the voltage shoots up, there's an open sense circuit going to the alternator.
(4) if you've still had no luck, shut the engine off and double check your connections at the back of the alternator. there should be that 2-wire gray connector, the thick wires connected to the big screw terminal, and some thin ground wires connected to the alternator's frame. make sure the connections are clean and not corroded or oxidized. clean them off, then try it again.
there's more, but try these and let us know what you find.
Dan
12-02-2004, 08:59 AM
#5
Senior Member
Thread Starter
Join Date: Aug 2002
Posts: 196
Sounds like the detail I need. I'll be leaving in a bit to go look at the car. I'll print this out and let you know what happens.
thanks for the help. If anybody has more info or suggestions feel free to continue posting...just in case I don't find the problem.
thanks for the help. If anybody has more info or suggestions feel free to continue posting...just in case I don't find the problem.
12-03-2004, 06:59 PM
#7
Senior Member
Thread Starter
Join Date: Aug 2002
Posts: 196
Ok...I did the checks you suggested and it passed. I then decided to look at the trusty Haynes manual (they aren't FSM, but better than nothing), but it was really not very helpful since all the letter they said were on the back of the alternator didn't match up with the letters on the back of the one I had.
So...since the guy at AutoZone was too busy trying to interrupt and tell me the problem before I could tell him the symptoms, and didn't want to exchange it for another one....
My buddy took it to another AutoZone, where we found that the guy above had a reputation for being that way... and they swapped it out. The new alternator is in now and not having problems. We'll just keep an eye on it for a few days to be sure.
Thanks for your help on this.
So...since the guy at AutoZone was too busy trying to interrupt and tell me the problem before I could tell him the symptoms, and didn't want to exchange it for another one....
My buddy took it to another AutoZone, where we found that the guy above had a reputation for being that way... and they swapped it out. The new alternator is in now and not having problems. We'll just keep an eye on it for a few days to be sure.
Thanks for your help on this.
04-24-2009, 09:08 AM
#10
Newbie - Just Registered
Join Date: Apr 2009
Posts: 1
I know that I am digging this up from a long time ago but I have a question in regards to the two wire plug on the top of the alternator, mine broke off when I was changing out the alternator on my 97 maxima. Can somebody tell me if you are standing on the passenger side looking down at the alternator in the top plug, which wire is in on the left and which is on the right? I am making a new plug and want to be sure to get this right. I have been searching for days but can't find anything. Any help would be appreciated. Thanks.
Thread
Thread Starter
Forum
Replies
Last Post
TallTom
5th Generation Maxima (2000-2003)
50
07-08-2022 09:54 AM