Alternator not charging
03-01-2017, 11:01 AM
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Alternator not charging Hey guys I have an issue that has me about to pull my hair out. There are plenty of posts and threads about LS alternators not exciting and that seems to be my problem. I have tried every trick that has helped other people and I put od ideas.
My motor is a 5.3. I have LS1 intake and accessories. Alternator is from an 05 gto. Harness was built by PSI conversion. I just recently got vehicle started and running to find that my alternator isn't charging. I have taken it to 2 different stores to have it tested and every time it passes, putting out 14.x volts. All grounds are solid and large gauge wire. I did have to modify my alternator plug as my original harness had the 1 red wire. I added the white wire (battery voltage) with instructions from PSI conversion. With key on white battery voltage wire has 14.x volts, and red exciter wire has 12 volts.
I tried buying correct alternator (truck style) single red wire into the 4 terminal plug and that did not fix the issue. I have tried putting in resistor to the red wire, with no luck.
With large battery connectes cable removed from alternator it shows on that post under 1 volt as the car runs. Which makes me think alternator is not exciting.
Any help is appreciated. I've tried everything in my power. Maybe eve suggest somebody or shop in Modesto CA area who I could hire to help me. Thanks in advance!
My motor is a 5.3. I have LS1 intake and accessories. Alternator is from an 05 gto. Harness was built by PSI conversion. I just recently got vehicle started and running to find that my alternator isn't charging. I have taken it to 2 different stores to have it tested and every time it passes, putting out 14.x volts. All grounds are solid and large gauge wire. I did have to modify my alternator plug as my original harness had the 1 red wire. I added the white wire (battery voltage) with instructions from PSI conversion. With key on white battery voltage wire has 14.x volts, and red exciter wire has 12 volts.
I tried buying correct alternator (truck style) single red wire into the 4 terminal plug and that did not fix the issue. I have tried putting in resistor to the red wire, with no luck.
With large battery connectes cable removed from alternator it shows on that post under 1 volt as the car runs. Which makes me think alternator is not exciting.
Any help is appreciated. I've tried everything in my power. Maybe eve suggest somebody or shop in Modesto CA area who I could hire to help me. Thanks in advance!
03-23-2017, 07:47 PM
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It is possible to be a PCM issue, that it isnt sending the 8v needed to "excite" the exciter wire (the thin red wire). Ive herd that the resistor trick is a hit or miss. I wouldn't have a clue how to test it since I don't know when the PCM is suppose to send voltage, I assume it is when the battery is under a certain threshold. Though you might be able to test it by starting the car with the exciter wire pulled from the alternator and testing it with a multimeter. If there is about 7-8 volts or more then the only other issue I could think of is following that thick *** cable that goes to the battery and check it for any cracks/damage/corrosion on the terminals are either point.
Best of Luck!
Best of Luck!
