Battery light coming on?

DANIELSHEA100

MEMBER
2000 FORD WINDSTAR
3.8L
V6
2WD
AUTOMATIC
3,747,284 MILES

So, the battery light on my minivan was coming on when I stopped for a period and the dash lights were dimming and brightening. So, I had it tested, and they said that the battery was good, and the alternator checked out good, but the voltage was going up and down, so I went ahead and changed the alternator because they said that that is a sign of it going bad. Then I drove it and it came on again when I stopped for a period, what else do I need to check is there a fuse somewhere? Please help minivan is my fiancé and it is her work vehicle she cleans houses for a living.

5 Replies

KEN L

MASTER CERTIFIED MECHANIC
47,722 POSTS

It sounds like one of the fusible links has one out or is weak, I would use this guide to check the connections and I have included the alternator wiring diagrams so you can see how the system works and which wires to test.

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

Check out the images (below). Please let us know what happens.

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Tuesday, April 4th, 2023 AT 10:38 AM

DANIELSHEA100

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3 POSTS

I talked to a good friend of mine that works as a mechanic attic mechanic shop, and he said the easiest and cheapest way to fix it would be to run a 10-gauge wire straight from the alternator to the positive side of the battery. He said that will bypass the fusible links if one is bad. What do you think? I want a second opinion.

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Wednesday, April 5th, 2023 AT 5:06 AM

KEN L

MASTER CERTIFIED MECHANIC
47,722 POSTS

Yep, that will work, also test the remaining fusible it is easy to do. Let me know what happens.

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Thursday, April 6th, 2023 AT 11:01 AM

DANIELSHEA100

MEMBER
3 POSTS

I put the 10 gauge wire straight from the alternator to the positive side of the battery and that did not work battery light still came on.

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Thursday, April 6th, 2023 AT 11:05 AM

KEN L

MASTER CERTIFIED MECHANIC
47,722 POSTS

Did you check the fusible links? You may have a bad PCM or instrument cluster. I would do a CAN scan; you can get a CAN scanner (Controller Area Network) from Amazon.

Here is a video to show you how:

https://youtu.be/u-4syLc-ifQ

and

https://www.2carpros.com/articles/can-scan-controller-area-network-easy

Here is one for about $99.00 if you need it:

https://amzn.to/3ZixY4v