: Volt guage fluctuation

04-08-05, 05:01 PM
Is it normal for the volt meter to go down to just about in the red when you have the heated seats, rear defrost, radio, heat, and headlights on at the same time? This was a common occurance this winter when I was driving at night. I would notice the guage drop almost into the red so I would turn off the seats and the rear defrost and the guage would slowly move back up to the center. Just wondering if this happens to others or if I have a short in the seat or defrost.

04-08-05, 05:36 PM
I also experience the same thing with my 97 during this past winter. But it won't go down to near the red. If my calculation is correct, it goes down to about 10 volts. But just like Steve said, if the headlight doesn't dim when idle, there should be no problem about it. And I never see that dimming symptom so I just let it be and enjoy the ride. Actually, when you are running a little faster, the voltage goes up to about 11.

04-10-05, 04:39 PM
i actually had my 99 checked out for the same issue, especially when rear defrost was engaged this winter the voltage would drop to just above red at stop lights, since the car was under warranty the cadillac dealership told me it was normal, that headlights combined with the rear defog/defrost was a heavy load, especially while the car has kicked down and braked pulling up to a light, i'm a tech myself and i find it odd that the car does this, i put in an interstate {MTP-91} battery and it didnt change. my car also dips down with rpm and votage while slowing to stops the kicks up and voltage follows, the gm techs have servie bulletins they can print for you explaining why, but it is normal. just be sure that u dont have those seats on for no reason, same with defog/defrost because really thats what kills batteries over time.

Smokin' 04 CTS
04-11-05, 04:41 AM
It sounds like a weak or dying alternator. I had this same problem in another car of mine, it just kept getting worse. Once the car almost turned off on me, and the voltmeter would drop below normal range. You could either upgrade the bearings on the alternator, or upgrade to a newer one. I ended up getting a new alternator and all those problems were fixed.