2002 Chevy venture electrical problem

I am having problem with the battery light coming on headlights on when switch is off the fule gauge dancing up and down radio works intermittently that's when I start the van it will only run a few miles and the battery will go completely flat I have changed the starter do not believe it is the alternator as there to many electrical problems thinking that a short somewhere can anyone PlEASE give advice as where to start and what to look at thanks

You need to test the alternator to rule it good or bad. Battery dropping below 12v can cause all type of symptoms. I would be checking battery cables, specifically all grounds.

I'd look at it as the alternator is causing all the electrical gremlins- system voltage drops can cause all kinds of havoc- so have the alternator tested- can be done on car at any autozone etc. System voltage needs to be 12.5+ at rest and near 14 or more when running. Internal battery shorts or even bad battery connections can also cause your issues.

Your battery light on is your biggest hint- chances are real good your alternator is going South...

If you charge battery and it runs a few miles, then quits, then you are not putting juice back into the battery- Put a DVOM on the battery terminals when running- better be near 13+ volts or you will die again due to bum alternator.

The vehicle battery light comes on at about 10.5 volts- system voltage- so you can believe that if you can't confirm with DVOM.

Radio will die near 9 volts- and gauges go crazy on low voltage- so every indicator you have tells me system voltage is low- not any shorts anywhere. Shorts would blow fuses.

You need to test the alternator to rule it good or bad. Battery dropping below 12v can cause all type of symptoms. I would be checking battery cables, specifically all grounds.
Thanks when I put battery on charger little black and decker it.say alternator ok fully charged reads 13v so maybe I will take out and test at auto zone