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

1990 CADILLAC DEVILLE
122,000 MILES • 4.5L • V8 • 2WD • AUTOMATIC
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BRODY HANSON
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  • 4 POSTS
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?
Aug 14, 2023 at 1:09 PM
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STRAILER
  • ✓ASE Certified Mechanic
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  • ASE Certified Mechanic
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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Aug 15, 2023 at 10:04 AM
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BRODY HANSON
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i believe we have figured it out, thanks.
Aug 15, 2023 at 9:50 PM
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STRAILER
  • ✓ASE Certified Mechanic
  • 54,837 POSTS
  • ASE Certified Mechanic
Can I ask what the problem was?
Aug 16, 2023 at 11:50 AM
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BRODY HANSON
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  • 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.
Aug 16, 2023 at 2:35 PM
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BRODY HANSON
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not dash but digital speedometer.
Aug 16, 2023 at 2:36 PM
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STRAILER
  • ✓ASE Certified Mechanic
  • 54,837 POSTS
  • ASE Certified Mechanic
Thanks for letting us know, we are here to help, please use 2CarPros anytime.
Aug 17, 2023 at 10:14 AM
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