Voltmeter Question

[garagegoon]

Hello to all... I have a small problem... I own a 2005 silverado withe the V6 WT. I have owned it since new and the voltage on the dash has never fallen below the 14 mark. Now, and only during the day, it falls to just above 12 and stays there.

At nite, withe everything running even, it is normal. Just during the day it falls to that level.

No warning lights or error messages... weird..

Anyone have any suggestions.

I have tested the alt and bat and they checked out fine...


Dave

[Crawdaddy]

sounds like a bad connection somewhere that breaks when the heat from the sun heats it up. Probably on the wire that signals the alternator to start producing power, which of course I forgot. I think it's the field wire, and I'm not quite sure what color it would be.

[garagegoon]

If that were the case then the heat of the engine would do the same thing. And its been cloudy and butt azz cold out... external heat source is eliminated.

[vncj96]

I really wouldnt worry about I guess, if everything is running normally and no dimming of head lights at night. Just keep an eye on it. But for piece of mind check all connections for corrosion, including the main line to the starter and from the starter on up.

[garagegoon]

oky doky... though my engine is clean enough to eat off of... ... I will keep my eye on it. Thanks

[garagegoon]

I have it narrowed down to turning on the lights. When i turn on the headlights the voltage stays normal, about 14.4. When i turn off the headlights the voltage drops to around 12 and sum change.

[vncj96]

Ok that is weird! Are the daytime lights drawing too much power, try pulling the fuse for the daytime lights and see what happens.

[garagegoon]

With the daytime running lights not on it still does it. Then i flip the switch to turn headlights on and up comes the voltage. Its a slow climb...takes about a min... but it goes back to 14.4 give or take.

[jprimrose4292]

sounds like it could be the regulator in the alternator.

[JMoney02]

Quite probably the regulator, appears to drop between off and on. How does the meter change when you power on the whole system? I mean everything, during the day and during the night. Turn all accessories and the lights during the day with the truck off, then on. Then test this again at night(if it isn't that cold) and see what your readings are. This will somewhat get a bench mark of variations(alt, bat, headlight switch and so on). Generally it's been the regulator causing the issue. How old it the battery? Three years? What kind of test has been performed on it? Load test on Alt/Bat also? Let us know....Jeff