The alternator caught on fire and the car will only run off the battery?

BRODY HANSON

MEMBER
1990 CADILLAC DEVILLE
4.5L
V8
2WD
AUTOMATIC
122,000 MILES

My car listed above alternator started on fire, so we replaced the alternator and alternator plug, tested all the wires that are hooked up to the alternator and battery and all tested okay. I was looking at the dash while starting it and noticed the battery light is gone on the speedometer, we went looking around to try to find the base to the battery light in the dash and couldn’t find it anywhere. I just want to know where you might find one or what our problem could potentially be?

6 Replies

KEN L

MASTER CERTIFIED MECHANIC
48,363 POSTS

Yes, check fuse #7 in the fuse panel on the left side of the instrument panel. Here is an alternator wiring diagram so you can see how the system works. Check out the images (below). Please let us know what happens.

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Tuesday, August 15th, 2023 AT 10:04 AM

BRODY HANSON

MEMBER
4 POSTS

I believe we have figured it out, thanks.

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Tuesday, August 15th, 2023 AT 9:50 PM

KEN L

MASTER CERTIFIED MECHANIC
48,363 POSTS

Can I ask what the problem was?

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Wednesday, August 16th, 2023 AT 11:50 AM

BRODY HANSON

MEMBER
4 POSTS

We ordered a new dash because the diode on the battery low light for the dash went out. When the alternator started on fire and a mechanic told us that the battery cannot charge or be charged by the alternator unless that diode works.

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Wednesday, August 16th, 2023 AT 2:35 PM

BRODY HANSON