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Registered
1992 Seville STS & 1991 Sedan Deville
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181 Posts
Discussion Starter #1
Only shows this message when I am accelerating like on the highway. Once I get off the gas pedal she goes back to normal. The local alternator rebuilder says this is normal but my brothers Deville does not do this. Any ideas or should I just replace the unit?
 

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Master of the Dark Art of Diagnostics
2003 DHS - two-2002 DHS, 2003 SLS, 1995 Sedan DeVille, 1989 Coupe DeVille
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20,215 Posts
The local alternator rebuilder says this is normal
the local alternator rebuilder is WRONG -

now give us a better description of what is going on -

what message - EXACTLY - are you getting -

and when - EXACTLY - are you getting it -

can you predict when the message will appear -

does it happen every time you accelerate -

what is the battery voltage with KEY-ON - ENGINE OFF -

what is the voltage with the engine running at idle speed -
 

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Registered
1992 Seville STS & 1991 Sedan Deville
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181 Posts
Discussion Starter #3
Okay the exact message is Battery Has No Charge, only says that when I am really getting in it say like an on ramp to the expressway or need to pass someone quick like. Other than that it appears normal. 14.4-14.2 when first starting and 13.9-13.6 once she has been running awhile. However in my experiences I have never seen an alternator go up and down in voltage as much as this one. Battery voltage is normal 12.9 -13.1 with the car off, and with key on car off voltage stays within that range.

I am fairly handy with electrical wiring but this all appears to be the alternator all of the wiring to and from the alternator is in good shape and has no resistance according to my ohmeter.
 

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Registered
1997 Cadillac STS (BOSE w/AUX In, Massage Seats, URPAS, "Z")
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6,405 Posts
The actual message is "BATTERY NO CHARGING" and it means your alternator is (going) BAD! and NO that message is NOT normal.
The voltage should vary anywhere in between 12.2V and 14.8V. When running should be in the first 10 minutes ~14.2V and then should progressively drop to 13.6V or so once the battery is charged. When idling (at night - headlamps on) you may see 13.2V then once you move you get back to 13.4V-13.6V.

Soon you will be stranded on the side of the road with a dead battery, the alternator is not charging the battery as it should, at some point you will run off the battery.
The alternators are not very reliable on my experience, I am at my 4-th now (176K), I have seen that message allot the days before replacing the alternators.
 

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Registered
1997 Seville STS, 2000 Seville STS
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1,694 Posts
Ever change the serpentine belt? Since it only occurs on a rapid change of engine rpm before jumping into an alternator replacement I would look to see how tight the serpentine belt is. If its loose it could be slipping on the alternator pully. Is it hard to steer at any time, like it has no power assist?
 
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