with lights and heater on, it turns the battery light on?

1996 DODGE RAM

17,600 MILES • V8 • 2WD • AUTOMATIC

TRAVIS RAYMO

MEMBER
1 POST
FOLLOW

replaced alternator and battery, my gauge in the truck used to go to 14. with both parts replaced, it only goes to 12 now. Why is this? with lights and heater on, it kicks the gen. light on and slowly starts losing its charge?

Dec 28, 2009 at 7:28 PM

Repair Safety Notice: This information is for general instructional purposes only. Vehicle repair can be dangerous. Verify all information, follow manufacturer service procedures, use proper tools and safety equipment, and consult a qualified repair shop when needed.

SQM

AUTOMOTIVE REPAIR CONTRIBUTOR
6,383 POSTS

Hello,

The battery light turns on when the battery is not getting adequate charge from the alternator.

It could be due to a bad alternator as well as faulty wiring.
First check to see the alternator output to the battery.

Here is a helpful video that shows how to test the alternator:

https://youtu.be/Z-p4dMJUpUw

Check for any corrosion on the alternator cable. Clean if necessary.

It is possible to have a defective alternator that is not performing as it is designed to underload.

I have attached diagrams for your reference.

Please let me know if you have any questions.
Thank you.

Images (Click to enlarge)

Dec 12, 2021 at 8:51 PM