99 Tahoe Volt drops from 15v to 13v

[Cholo Mike]

Hi Need help!

I have a 99 Tahoe 4door 4 wheel drive LT.
I had a problem with voltage this last year. replaced batterie, alternator , tensioner, and starter. I went out to lake pleasant for the weekend and i went swimming came back about 6 hours later would not start.i finally after 2 hours got it to start. drove to Auto Zone guy said starter. so i replaced it. then i started the truck and it started right up. the next day same thing truck would not start. so i was told to try the batterie and shure enough started right up. then i noticed the voltage gauge droped to 12v went to auto zone and they said alternator. i replaced that and it started right up. the next day i had a voltage problum again between 11v to 16 v on and off. so i went in they told me try the tensnoir and i replaced that. now i start my truck and drive at 15v and after 30min it drops down to 13v and it goes up and down all day. can anybody help. i have run out of ideas! thank you

[MT-2500]

Originally Posted by Cholo Mike

Hi Need help!

I have a 99 Tahoe 4door 4 wheel drive LT.
I had a problem with voltage this last year. replaced batterie, alternator , tensioner, and starter. I went out to lake pleasant for the weekend and i went swimming came back about 6 hours later would not start.i finally after 2 hours got it to start. drove to Auto Zone guy said starter. so i replaced it. then i started the truck and it started right up. the next day same thing truck would not start. so i was told to try the batterie and shure enough started right up. then i noticed the voltage gauge droped to 12v went to auto zone and they said alternator. i replaced that and it started right up. the next day i had a voltage problum again between 11v to 16 v on and off. so i went in they told me try the tensnoir and i replaced that. now i start my truck and drive at 15v and after 30min it drops down to 13v and it goes up and down all day. can anybody help. i have run out of ideas! thank you

Well after all of the throwng parts at it.
Is the battery going dead after setting now fixed?

If you are going by dash gauge volt meter.
They are not a good or true volt meter.

Get a volt meter on battery and see what the reading is there.
Post back that reading.
Also check for amp draw engine off.

[Cholo Mike]

I went out side and with the truck off it sits at 12.4v.
-truck off lights on 12.1v
-truck on 14.3
-alt 14.6
truck on heater on 14.1

the volt meter on the truck while after driving on the road will go up and down not rapidly threw out the drive with nothing different just driving to low 13v to high 15v sometimes 16v? its confusing.

[MT-2500]

Originally Posted by Cholo Mike

I went out side and with the truck off it sits at 12.4v.
-truck off lights on 12.1v
-truck on 14.3
-alt 14.6
truck on heater on 14.1

the volt meter on the truck while after driving on the road will go up and down not rapidly threw out the drive with nothing different just driving to low 13v to high 15v sometimes 16v? its confusing.

As said the truck volt meter is not a true good volt meter.

Watch voltage with a good volt meter while driving.

Is the battery still going down sitting?