Battery light on, battery draining?

SCOTT BROWN6

MEMBER
1999 FORD EXPEDITION
4.6L
V8
4WD
AUTOMATIC
285,000 MILES

The vehicle is having some charging issues. I already replaced the alternator tensioner and the battery and it still has the battery light on and it's draining the battery in about 15 minutes. I've checked all the fuses all the wires the fusible link I have checked it all is there a relay or something that I'm not finding or knowing about I've watched dozens of videos on YouTube, and I cannot figure this out 3 days now I need that rig to run so I can make my money. Thank you

Friday, October 21st, 2022 AT 5:27 PM

1 Reply

JACOBANDNICKOLAS

MECHANIC
110,176 POSTS

Hi,

Are you getting power at the black wire with the orange tracer at the alternator? If not, there could be an issue with the starter relay.

Take a look at the pics below. They are the schematics for the charging circuit. Check the aforementioned wire for power.

Next, the idea that the battery drains in 15 minutes is concerning. That sounds like there could be a short at some point.

Check to make sure there isn't an issue at the starter relay and let me know what you find.

Also, if you haven't already, check to see if the alternator is charging when the engine is running. All you need is a voltmeter or multimeter.

Here is a link that shows how to check:

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

Let me know.

Take care,

Joe

See pics below.

Images (Click to make bigger)