Alternator wire digram

[MoneyTrell]

Hey for some reason my alternator is not charging, I have replaced the alternator,battery and starter and it was working good for a few months then it pooped on me again. I am trying to figure out why it not charging it seems like the alternator is not putting out enough volts to charge the battery i think it might be a short some where but not sure where. What are some test i can do to figure out whats wrong.

[fdryer]

While not having access to wiring diagrams (try http://workshop-manuals.com/), virtually all alternators have one main power wire connected to a side terminal on the frame and a connector w/wires for the electronics. The HOT wire is always called the fusible link wire as it is a calibrated fine wire to act as the only fuse in case the alternator suffers an internal short circuit. The fusible link wire simply cooks and burns out, sometimes leaving no evidence of it burning out as in most fuses that can be seen as either good or blown. Other than ensuring the wiring was replaced correctly, either this wire was overtightened and a backup wrench wasn't used as the lock nut twisted the mounting stud, breaking off the internal wire or the fusible link is blown.

The easiest test to determine if the fusible link is intact and correctly wired; the main battery cable to the starter also has this small gauge fusible link wire attached to the same terminal on the starter as the battery cable. Measure the starter terminal with both wires for 12v. Engine or frame ground for the negative probe. Once you see 12v on the starter terminal, the small gauge fusible link wire goes to the alternator side terminal and is HOT. Measure the alternator side terminal as it should have 12 volts. If you have 12 volts on the side terminal of the alternator, either the alternator failed or the serpentine belt is loose and not driving the alternator. If 12 volts isn't seen on this terminal, the fusible link wire burned out and needs to be replaced. Fusible link wires are rated for around 30 amps and is not used for recharging the battery. Frame ground is where current returns from the alternator to supply up to the maximum current output of alternators (85-250 amps).

When the electrical system is operating correctly, battery voltage should measure around 12.5v/engine off, 14.5v/engine idling. The higher voltage, all voltages measured at the battery terminals, is the alternator always supplying all the electrical power the car needs while slow charging the battery. Less than 14 volts with engine idling means either the drive belt is slipping, faulty alternator, fusible link fault or incorrect wiring when replacing the alternator.

[MoneyTrell]

Alright, I will test the battery/starter/alternator and make sure they all have some voltage coming to them first. If one is not i will replace the red wire fusible link..

I will also test and see if i can find a short anywhere with my short circuit tester.

[MoneyTrell]

I think i figure the problem. The alternator is not producing enough volts to the battery. The diodes pass the test but the volt regulator did not pass so it needs a new alternator. I also disconnected the positive terminal from the battery and tested it with a volt meter and it was only reading around 10.64v witch shows the alternator is not producing enough because it should be like 13 or so.

[Aashi]

Originally Posted by MoneyTrell

I think i figure the problem. The alternator is not producing enough volts to the battery. The diodes pass the test but the volt regulator did not pass so it needs a new alternator. I also disconnected the positive terminal from the battery and tested it with a volt meter and it was only reading around 10.64v witch shows the alternator is not producing enough because it should be like 13 or so.

Hi guys

Based on your observations, it does seem like the alternator is the culprit behind the insufficient voltage reaching the battery. The fact that the diodes passed the test indicates they are functioning correctly, but the failed voltage regulator suggests the need for a replacement alternator.Free Fire