its parked i unpluged the battery but i figured everything has an inter changable part that matches the original part
“but when i unhook th positive terminal from the battery the van shuts off so it has to be the alternator”
There’s no way in telling what kind of damage has been done to the alternator or the computer for that matter.
http://www.troubleshooters.com/dont_disconnect_battery.htm
Tester
@gabe21 That’s not what is generally meant by interchangeability, which really means a part from one car can be a match for another.
Uniform parts matching and manufacturing was invented by Cadillac over 100 years ago, allowing mass manufacturing.
As advised get a competent mechanic diagnose first what your problem is before you accidentally do more damage. I stopped fixing my TVs a long time ago and now let an expert do it.