voltage meter in 1995 jeep grand cherokee

[bhs91]

I have noticed recently that my dash mounted voltage meter has some swings to it as i drive. When i am idling, it drops, when i speed up it is "normal". The range is from 9-19 and normal is around 12-13, but when I idle it drops to around 9. Is this an idication of a battery going bad, or the alternator or do i have a loose belt? Or is it normal since I usually have the heat going full bore this last few weeks?

Thanks,

BHS

[Macgyver55]

Batteries have heavier loads on them during the winter so it becomes more difficult for the battery and charging system to keep up. As you said, the heater is on, lights are on more (shorter days), dirty windshields mean wipers get used more, electric seat(on some) rear window defrosters. You get the idea, there is usually extra loads on a system during the winter so its not unlikely that the alternator is at capacity and at idle it is either barely/not filling the battery's need. If it charges normal at speed thats a good thing, it says its doing ok there. You could try shutting everthing off at idle and see what it looks like then. If you are not having problems with it starting at these temps chances are its ok.

The only way to know for sure if you are concerned is to do a load test on the battery and charging system to verify the output.

[Shack]

Mac55 Does bring up good points, but I have seen a fair share of voltage regulators puke on these.

If I recall, 4.0L or the 5.2L, the VR is internal on the alternator.

Last year on a 87 Ram plow truck I have did the same thing and turned out to voltage regulator. That one was separate from the alternator and was mounted on the fire wall though.

[bhs91]

10-4 Thanks Macgyver!!

[BIG DS]

get it checked. Does the gauge "bounce" when the turn signal is turned on? That is a pretty good indicator that trouble is brewing in the alternator. With the cold weather that has been in the area, I would say a starting/charging system test would be money well spent. If something needs to be replaced, a lot of garages will waive the test fee. Don't be surprised if you end up buying a battery and a alternator. Better safe than sorry.