Would it hurt the alternator to do what? To leave the leads on the signal wire? or to drive with an alternator that is not charging? What were your test results? 
Charging problems HELP PLEASE!!!
Thread Starter
Teching In
Joined: Feb 2009
Posts: 17
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From: phoenix, az
Charging problems HELP PLEASE!!! I have a 2001 trans am, and i had a stator short out in my alternator. i replaced the alternator, and now my atl. cuts in and out around evrey 2-5 mins and if i go over about 2200 rpm it will completly turn off. I tested my signal wire and it had system voltage but i didnt test it with the engine running. and the battery is good and all conections are good. Anyone have any idea what is going on, or ever had this problem?
Staging Lane
Joined: Jun 2009
Posts: 54
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From: MN
i am having a a problem like this on my 99 TA. i was out driving with some buddys, we where driving hard for about 50 miles when i looked down and saw that the volts where at 12. i put a new alt in and checked the battery, 12.5V, signal wire, 12.5V, with the car off and both at 11.3 when running with the lights on not a clue whats going on and need some help. any ideas
On The Tree
Joined: Mar 2008
Posts: 150
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From: Acworth, GA
crap part? I've seen some junk come out of aftermarket parts stores - especially autozone. Try doing a voltage drop test on the signal wire and main cable. If that tests good, your battery and connections are good, and your serp belt is actually turning the alternator - then go buy a better alternator.
Staging Lane
Joined: Jun 2009
Posts: 54
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From: MN
this is the 2nd alt i got from the store and it is a acdelco alt. and i know that it is good i had it tested
how do i do a voltage drop test?
what am i looking for?
i know varry little about testing when it comes to the wires
how do i do a voltage drop test?
what am i looking for?
i know varry little about testing when it comes to the wires
On The Tree
Joined: Mar 2008
Posts: 150
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From: Acworth, GA
You have to have a voltmeter ( a decent one preferably ). Set it to volts dc. Hook one lead to the main post (positive) on alternator. Hook other lead to positive post on battery. Crank engine and load system down (a/c, headlights, highbeams, etc). Check reading on voltmeter. Should be less than 500mv (0.5v). Preferrably less than 300mv (0.3volt). If it is less than that wire is good. If it is more (like 2-3 volts or higher, like 12-13 volts) than you need to replace the wire to your alternator.
The same test applies to the signal wire - one lead on wire at alternator, other lead on battery positive.
The same test applies to the signal wire - one lead on wire at alternator, other lead on battery positive.
Staging Lane
Joined: Jun 2009
Posts: 54
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From: MN
ok thats what i was doing then. was hard to get at the signal but i got it. dont have a clue what to do is it going to hurt anything if i drive it to the dealer like this? i dont want to have to pay another 200 for a new alt cuz i recked it
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On The Tree
Joined: Mar 2008
Posts: 150
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From: Acworth, GA
This is a rather simple issue to figure out and you have people here willing to help you - so the man (dealer) doesn't stick it to you (or in you).
I read your reply again - I guess maybe youre trying to drive with the voltmeter hooked to the wires ?? - do NOT do that. It's not necessary. I don't really know where youre at with it. Let me know and I can tell you what to do next.
I read your reply again - I guess maybe youre trying to drive with the voltmeter hooked to the wires ?? - do NOT do that. It's not necessary. I don't really know where youre at with it. Let me know and I can tell you what to do next.
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Verdad Gallardo Staging Lane
Joined: Jun 2009
Posts: 54
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From: MN
sorry, the test came out just fine on the main wire to the battery. the signal wire is extremly hard to get to with it hooked into place but i will be trying again.
i was asking if i drove the car to the dealer or even to work for that matter if i would hurt the Alt. or the Battery or anything. just driving the car all hooked up normal.
when i bought the alt they told me that if the battery was not on a full charge that it would fry the alt, why that would be i dont know, to me that says that every time someone starts there car on a dead battery you would hav to buy a new alt? how dose that work?
i dont want to have to bring the car so i do like all the help you are giving me im just no good when it comes to a wireing problem. and dont know what to do.
i was asking if i drove the car to the dealer or even to work for that matter if i would hurt the Alt. or the Battery or anything. just driving the car all hooked up normal.
when i bought the alt they told me that if the battery was not on a full charge that it would fry the alt, why that would be i dont know, to me that says that every time someone starts there car on a dead battery you would hav to buy a new alt? how dose that work?
i dont want to have to bring the car so i do like all the help you are giving me im just no good when it comes to a wireing problem. and dont know what to do.
Staging Lane
Joined: Jun 2009
Posts: 54
Likes: 0
From: MN
i was just thinking about it but is there a chance that i could have pulled the signal wire out of the connector? i know that the wire is not broken, at least not anywhere that i can see, but is that even posible? pulling it only part way out of the conector that is?
On The Tree
Joined: Mar 2008
Posts: 150
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From: Acworth, GA
I would not drive the car with an alternator that is not charging. Not only are you killing the battery's life, but you risk the chance of damaging other electrical items like the pcm, and you could possibly stall out in an intersection which is not a great thing.
It is very possible the wire came out or the internal strand of wire may have broken at the connector - Its happened to me on my personal car as well as customers cars. It is a high heat area so that little tiny wire takes a lot of abuse.
I know its a pain to get to, and I assume you don't have a lift to get under the car easily. Lately, I have been just cutting the connector off and splicing in a stereo speaker connector (it is the same size terminal). It works great. The reason I do this instead of getting a new connector from GM is because the connector is around 40 bucks which = bullshit.
I also add a few inches of wire to make it easier to tie out of the way.
Good luck.
It is very possible the wire came out or the internal strand of wire may have broken at the connector - Its happened to me on my personal car as well as customers cars. It is a high heat area so that little tiny wire takes a lot of abuse.
I know its a pain to get to, and I assume you don't have a lift to get under the car easily. Lately, I have been just cutting the connector off and splicing in a stereo speaker connector (it is the same size terminal). It works great. The reason I do this instead of getting a new connector from GM is because the connector is around 40 bucks which = bullshit.
I also add a few inches of wire to make it easier to tie out of the way.
Good luck.
On The Tree
Joined: Mar 2008
Posts: 150
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From: Acworth, GA
Another simple test to see if that wire current is good without doing the voltage drop test - take a test light (if you don't have one, you can buy a cheap one for like 6 bucks at the parts store). Engine off, take the signal wire off and insert the probe into the connector and clip the other end to ground (body of alternator of ground cable at the block near the motor mount), then turn the key to the run position. See if the light comes on. If not, you have a wire problem. If it does, replace your alternator.
Staging Lane
Joined: Jun 2009
Posts: 54
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From: MN
alright i will try that with the teast lite then.
i was thinking wile i was at work today and i know that that wire tells the alt to start charging but wouldnt it also cary the numbers for the in dash volt gauge as well? and if that reads the same as what the battery reads then to me that would say that the alt is good. i could be wrong and would not doute it. i did get a C in elc 101 in collage. i have just never been able to understand it all and i wish that i could.
is that where the wire tends to go bad? at the connector? i dont want to add wire just to find out that it was .5 inches higher then where i spliced it at. i have to tool to fish out the wire from the connector so i will just reuse that i just dont want to run into a mess that i cant fix.
i could care less about the battery i need to get a new one soon anyway but i dont want to mess anything else up thats why i asked.
thanks for the help and i would like anymore that you have. just trying to learn ya know.
i was thinking wile i was at work today and i know that that wire tells the alt to start charging but wouldnt it also cary the numbers for the in dash volt gauge as well? and if that reads the same as what the battery reads then to me that would say that the alt is good. i could be wrong and would not doute it. i did get a C in elc 101 in collage. i have just never been able to understand it all and i wish that i could.
is that where the wire tends to go bad? at the connector? i dont want to add wire just to find out that it was .5 inches higher then where i spliced it at. i have to tool to fish out the wire from the connector so i will just reuse that i just dont want to run into a mess that i cant fix.
i could care less about the battery i need to get a new one soon anyway but i dont want to mess anything else up thats why i asked.
thanks for the help and i would like anymore that you have. just trying to learn ya know.
Staging Lane
Joined: Jun 2009
Posts: 54
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From: MN
do you know of anygood books that i could get to help with the learning prosses on the elc. end of things? i have my books from when i was in school but nothing on elc. they where worth to much and i didnt keep them. and where no good to me when i swtched majors, wish i would have keeped them now
On The Tree
Joined: Mar 2008
Posts: 150
Likes: 0
From: Acworth, GA
i was thinking wile i was at work today and i know that that wire tells the alt to start charging but wouldnt it also cary the numbers for the in dash volt gauge as well? and if that reads the same as what the battery reads then to me that would say that the alt is good.
There is plenty you can learn on the internet without spending money on books. For example, search voltage drop testing in youtube. A bunch of videos are available to teach you what you want to know.
Staging Lane
Joined: Jun 2009
Posts: 54
Likes: 0
From: MN
nothing seems to work, i cant find the proble. i spliced in a new wire at the top of the motor and in the connector. didnt help. cant seem to find the problem all the fuzes that i looked at where good but who knows maybe im looking at the wrong one. can you explain a little more as to where the fuze that im looking for is? im getting sick of not being able to drive the car and it kills me that i cant seem to find the problem. i have no clue what else to do. someone said that it could be the ECU but i dont know anymore. i hope its not but i cant test that at home so.
the car runs just fine just wont charge. all i wat to do is drive the car. i pulled it out this year to find that i had a bent rim and a broken tie sway bar link and that put the car down for 3 weeks do to the fact that it put me in the ditch at 45mph and i get it back and 3 days latter what do ya know it stops charging.
sorry boys and girls i just needed to vent a little. but anymore help would be great thanks alot
the car runs just fine just wont charge. all i wat to do is drive the car. i pulled it out this year to find that i had a bent rim and a broken tie sway bar link and that put the car down for 3 weeks do to the fact that it put me in the ditch at 45mph and i get it back and 3 days latter what do ya know it stops charging.
sorry boys and girls i just needed to vent a little. but anymore help would be great thanks alot
Staging Lane
Joined: Jun 2009
Posts: 54
Likes: 0
From: MN
It would make sence that it was slipping if it was charging at idel, but its not. unless it is slping all the time but the PS worked just fine wile i was driving it home and it didnt seem to be chopy at all so it dosnt seem likely that it is slipping at all
