HelP!!! MY ALTERNATOR WONT WORK
07-04-2011, 10:53 AM
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HelP!!! MY ALTERNATOR WONT WORK 2000 firebird ls1 is the motor
So i swapped the ls1 in to a 96 nisssan and drove it ran fine for like a hour and then my battery died.
so i figured its the alt took it out got it tested failed 4 time so bought a new one put it in and it and my battery didnt charge again and died new battery too
so i started to dig in.
the small wire is gettting 12v but for some reason the post on the back of the alt is not getting power and the light is lighting up negitve why would that be negitive would the alt just be bad or what ?
So i swapped the ls1 in to a 96 nisssan and drove it ran fine for like a hour and then my battery died.
so i figured its the alt took it out got it tested failed 4 time so bought a new one put it in and it and my battery didnt charge again and died new battery too
so i started to dig in.
the small wire is gettting 12v but for some reason the post on the back of the alt is not getting power and the light is lighting up negitve why would that be negitive would the alt just be bad or what ?
07-04-2011, 12:40 PM
#2
The post on the rear of the alternator does not "get" 12vdc it "gives"....that post is the output of the alternator. In other words the battery is charged by this post. The large gauge red wire that attaches there goes straight to the battery. Sounds like your wiring harness is not wired correctly on the car side where you spliced in the alternators wiring harness. This harness supplies negative and positive voltage to the alternators internal voltage regulator and also provides excitation voltage to cause the alternator to start charging the battery.
You will need to go back through a wiring diagram for your car and then compare it to a wiring diagram of any GM car/truck that used that engine/alternator setup and see where the problem lies. My bet is that you are not getting 12vdc ignition voltage to the correct or any wire at the alternator.
And stop using a test light! Voltmeters are easy to use and cheap. You can get a cheapy/usable one at Harbor Freight for $5. There are write-ups all over the internet that show you how to use them also.
You will need to go back through a wiring diagram for your car and then compare it to a wiring diagram of any GM car/truck that used that engine/alternator setup and see where the problem lies. My bet is that you are not getting 12vdc ignition voltage to the correct or any wire at the alternator.
And stop using a test light! Voltmeters are easy to use and cheap. You can get a cheapy/usable one at Harbor Freight for $5. There are write-ups all over the internet that show you how to use them also.
07-04-2011, 10:10 PM
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Also, never use your alternator as a battery charger. If a battery is dead, attach an actual charger or you can kill the alternator, particularly on vehicles newer than about 1983, where there is a generally higher need for voltage throughout the vehicle due to things like fuel injection and electronic ignition systems.
Alternators are designed to keep a battery charged, not to charge it once it has died.
Alternators are designed to keep a battery charged, not to charge it once it has died.
