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Discussion Starter #1
Hi gang,

I coldn't really find anything in the archives that looked like it was the same issue, so here goes:

I was driving home the other night, and I noticed that the headlights in my 2001 Deville dimmed for a quick second. At the same time, the fan on the AC slowed momentarily, then resumed it's original speed. I just got this car, so I don't know if it has always done this.

I'm guessing there was a quick drop in the voltage, so I displayed the voltmeter in the information center...sure enough, it happened again about 15 minutes later. Battery voltage dropped to 12.3 for about 5 seconds, then returned to 14.4. Is this normal for the newer Devilles? I haven't pulled codes yet, but everything else seems to be fine so I'm wondering if this is just a normal part of the electrical system's operation. It seems to happen about every 15 minutes, although I haven't timed it yet so I could be off there. If it is normal, does anyone know what the electrical system is doing at that point?

TIA,

-Mark
 

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Re: Electrical

2001blackdev said:
Hi gang,

I coldn't really find anything in the archives that looked like it was the same issue, so here goes:

I was driving home the other night, and I noticed that the headlights in my 2001 Deville dimmed for a quick second. At the same time, the fan on the AC slowed momentarily, then resumed it's original speed. I just got this car, so I don't know if it has always done this.

I'm guessing there was a quick drop in the voltage, so I displayed the voltmeter in the information center...sure enough, it happened again about 15 minutes later. Battery voltage dropped to 12.3 for about 5 seconds, then returned to 14.4. Is this normal for the newer Devilles? I haven't pulled codes yet, but everything else seems to be fine so I'm wondering if this is just a normal part of the electrical system's operation. It seems to happen about every 15 minutes, although I haven't timed it yet so I could be off there. If it is normal, does anyone know what the electrical system is doing at that point?

TIA,

-Mark
That's a new one on me....
 

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Re: Electrical

You need to have an amp meter on the alternator and then the battery to determine whether the system voltage is being drawn down by a large intermittent load, or if the alternator output is just intermittently dropping off. You COULD have a cooling fan problem and it's drawing down the system when it is activated. The other possibility would be that the load is normal but the battery is unable to carry it and dumping it entirely on the alternator.
 

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Re: Electrical

Katshot said:
You need to have an amp meter on the alternator and then the battery to determine whether the system voltage is being drawn down by a large intermittent load, or if the alternator output is just intermittently dropping off. You COULD have a cooling fan problem and it's drawing down the system when it is activated. The other possibility would be that the load is normal but the battery is unable to carry it and dumping it entirely on the alternator.
Cool, thanks for the suggestion...I can do that. You know, it's not really that noticable...maybe it's the AC compressor cycling on/off? The voltage drop only lasts a split second. You'd miss it if you blinked.

The good thing is the car is still covered under the factory warranty (and I plan on buying an extension from GM when it gets close to running out). So I'm not going to get way into troubleshooting it...I basically was just wondering if this was normal behavior for the car, and if not I'll have the dealer look at it.
 

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Re: Electrical

I'd have the dealer look at it for sure, but if your luck is anything like mine, they'll be telling you either that "the car operates to design spec" or "could not duplicate customer concern". These days, a problem has to be at about the level of somebody slapping you in the face before they seem to be able to find it, or feel that it's something that should be fixed. :rolleyes:
 

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Re: Electrical

Katshot said:
I'd have the dealer look at it for sure, but if your luck is anything like mine, they'll be telling you either that "the car operates to design spec" or "could not duplicate customer concern". These days, a problem has to be at about the level of somebody slapping you in the face before they seem to be able to find it, or feel that it's something that should be fixed. :rolleyes:
LOL...well, I don't have the best luck, but my wife teaches at the school where the owner of the dealership sends his kids. I've met him a few times during parent/teacher events. I don't know if that counts for anything in the service dept. , but it sure helped out during the sale. :D
 

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Re: Electrical

2001blackdev said:
LOL...well, I don't have the best luck, but my wife teaches at the school where the owner of the dealership sends his kids. I've met him a few times during parent/teacher events. I don't know if that counts for anything in the service dept. , but it sure helped out during the sale. :D
In July I bought a 2001 Deville. I have also had this issue 'pop' up a dozen times or so. It gets your attention. Very brief...maybe 1/2 second kind of thing. Exactly as you describe..lights and blower slow down for half a sec.

These cars are rolling massive computer systems. It could be something as simple as the battery age starting to show. We dont know yet. But if mine was doing this every 15 minutes something needs to be checked out.

All we really do is electrical work. Suspect #1 would be the grids in the battery starting to act up. Cadillacs are very sensitive to having a good battery.

Logan
 
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