Instrument panel and A/C controls are not working

Tiny
CRAIG_CLAUDIA
  • MEMBER
  • 2003 CADILLAC STS
  • 4.6L
  • V8
  • 2WD
  • AUTOMATIC
  • 180,000 MILES
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.
Friday, October 29th, 2021 AT 3:58 PM

4 Replies

Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
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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Saturday, October 30th, 2021 AT 4:01 AM
Tiny
CRAIG_CLAUDIA
  • MEMBER
  • 3 POSTS
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
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Saturday, October 30th, 2021 AT 10:19 PM
Tiny
CRAIG_CLAUDIA
  • MEMBER
  • 3 POSTS
Checking my notes, the new alternator was at 14.35 volts.
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Saturday, October 30th, 2021 AT 10:21 PM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
You are welcome.

Keep us updated.

Roy
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Sunday, October 31st, 2021 AT 2:32 PM

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