Vehicle not charging properly

JAMES MORRIS2

MEMBER
1993 JEEP WRANGLER
4.0L
6 CYL
4WD
MANUAL
123,000 MILES

The vehicle listed above is barely charging. I put a new alternator on and it's doing the same thing. Checked as much of connections that I could find. Thought it was the computer sent it off and they couldn't find a charging problem but changed diodes anyway. Still the same. Running its about 12.40v at the battery.

Thursday, July 23rd, 2020 AT 3:49 PM

2 Replies

ASEMASTER6371

MECHANIC
52,796 POSTS

Good evening,

It is not charging at all. 12.4 volts is battery voltage, not charging voltage. It should be 14 to 14.5 volts.

https://www.2carpros.com/articles/how-to-check-a-car-alternator

I attached the wiring diagram for you to view. You will need to check the fuses for power on both sides with a test light or voltmeter.

https://www.2carpros.com/articles/how-to-check-wiring

https://www.2carpros.com/articles/how-to-check-a-car-fuse

The engine ECM turns the alternator on and off based on load. Can you verify power to the alternator?

Roy

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Thursday, July 23rd, 2020 AT 4:37 PM

KASEKENNY

MECHANIC
18,907 POSTS

There are a couple things we need to check if we can assume the alternator is okay and the voltage regulator in the PCM is okay.

Let's start with making sure the belt is tight. If the belt is loose then it will slip on pulley and basically not spin the alternator.

Lastly, I attached the wiring diagram, measure the voltage on each of the wires and let me know what you have at the alternator. Thanks

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