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Discussion Starter · #1 · (Edited)
I have a 2009 DTS with 215,000 miles...
About a month ago my Service Charging System light on my dashboard came on. I figured the problem was a bad alternator and ending up replacing it with a remanufactured carquest one. Everything was working great for about a month. Today as I'm driving the Service Charging System light and message comes on the dashboard once more. So as I'm hurrying to get home, the voltage readout on the dashboard jumps between 11.6-11.7 volts, and at a stoplight it quickly dips down to 8.6 volts and triggers battery saver mode. I had an AAA technician come out and test the charging system - which read 8.62V for cranking volts (low), 10.68V alternator idle volts (low), 11.32V alternator load volts (low) and 0.12V diode ripple (normal). I've been scanning some of the forums but just can seem to pin point what might be wrong. Is this the case of a bad replacement alternator? Bad fusible link between the alternator and battery?
 

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Discussion Starter · #3 ·
Sounds like you have a dead cell in your battery.
Yeah? That's kind of what my hunch was. I was still concerned about those alternator readings the AAA tech gave me though that were signaling the alternator had gone bad too. Any thoughts on that?
 

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2006 Cadillac DTS 95k miles
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A bad battery can cause so many odd problems, it seems like a decent rule to follow is "Replace the battery first, if it's under 12 months or over 5 years old"

Does this jibe with what others have observed?
 

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I was still concerned about those alternator readings the AAA tech gave me though that were signaling the alternator had gone bad too. Any thoughts on that?
That is a possibility, especially being a "reman" alternator. If that's the case, you may want to consider a NEW A/C Delco alternator. I've always been leery of remans. You never know what parts where replaced or the quality or origin of those parts.
 

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Discussion Starter · #6 ·
A bad battery can cause so many odd problems, it seems like a decent rule to follow is "Replace the battery first, if it's under 12 months or over 5 years old"

Does this jibe with what others have observed?
I'll definitely give that a try next
 

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Discussion Starter · #7 ·
That is a possibility, especially being a "reman" alternator. If that's the case, you may want to consider a NEW A/C Delco alternator. I've always been leery of remans. You never know what parts where replaced or the quality or origin of those parts.
Yeah I'm learning that now :/ Is there a good place to get an AC Delco alternator? Seems the ones listed on Autozone's website are ~$300 more than the remanufactured ones
 

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2006 Cadillac DTS 95k miles
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That is a possibility, especially being a "reman" alternator. If that's the case, you may want to consider a NEW A/C Delco alternator. I've always been leery of remans. You never know what parts where replaced or the quality or origin of those parts.
It looks like the new generator is a mere $20 more than remanufactured
 

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2006 Cadillac DTS 95k miles
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Yeah I'm learning that now :/ Is there a good place to get an AC Delco alternator? Seems the ones listed on Autozone's website are ~$300 more than the remanufactured ones
Rock Auto's shipping can be expensive, it's cheaper if you have parts shipped to your office. Amazon carries the ACDelco part search for B01MRVD9G5
 

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Discussion Starter · #10 ·
Sounds like you have a dead cell in your battery.
So I just finished putting a new battery in the car about an hour ago to rule it out. No change. The red battery light in the dashboard came right back on right after starting up and driving for about 30 seconds. I guess Ill try a new alternator next
 

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So I just finished putting a new battery in the car about an hour ago to rule it out. No change. The red battery light in the dashboard came right back on right after starting up and driving for about 30 seconds. I guess Ill try a new alternator next
You didn't test the battery before replacing it?
 

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2006 DTS perf
2006 DTS Performance Lux III
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The alternator should put out 13-14 volts anything less and its bad. Even with a bad battery the alternator will try to compensate by charging as high as 15 volts. The DTS controls the voltage output of the alternator by the ECU Thats why its important to get a good quality alternator Even though its tempting because of the price stay away from reman alternators from auto parts stores. Rockauto will have what you need at the best price. sometimes you can luck out and find a newer alternator at the junkyard.
 
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