Instrument panel and A/C controls are not working

2003 CADILLAC STS
180,000 MILES • 4.6L • V8 • 2WD • AUTOMATIC
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CRAIG_CLAUDIA
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Everything else seems okay. new battery and alternator so far. Also, the door chimes ring even without the key in or lights on. i believe it is one of the body control modules, or the ignition switch. I can't afford a Tech 2 scan at the dealer, not sure that would help. How best to diagnose? I do have the huge service manuals...
Oct 29, 2021 at 3:58 PM
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ASEMASTER6371
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Good morning,

I attached the wiring diagram for the instrument cluster for you.

https://www.2carpros.com/articles/how-to-check-wiring

You need to test the 2 fuses I highlighted for power on both sides when the key is in the on position. 1 fuse is in the under-hood fuse block and the other is in the rear fuse block.

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

Let me know the results so we can proceed. Hopefully, it is just a failed fuse for you.

Roy

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Oct 30, 2021 at 4:01 AM
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CRAIG_CLAUDIA
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Roy,

Thanks for replying and your interest in my problem. I will test for power on both sides (with key on) of what looks like fuse #7 front, and #12 rear.
In the meantime, I finished the alternator replacement which fixed 2 issues, no more parasitic drain on the battery, output current a fairly steady 14.6 volts.
The old alternator showed 15.85 volts. Probably 1 bad diode in the rectifier?
I will check and report on the fuses sometime tomorrow. Thanks again!
Craig
Oct 30, 2021 at 10:19 PM
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CRAIG_CLAUDIA
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checking my notes, the new alternator was at 14.35 volts.
Oct 30, 2021 at 10:21 PM
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ASEMASTER6371
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You are welcome.

Keep us updated.

Roy
Oct 31, 2021 at 2:32 PM