Can anybody tell me why my alterrnator is charging at 18 volts over 2000 rpm? I have bought new alternators, 3 of them all do the same thing.
i connect it up like it shows, have switched every thing, when i take it to get tested they are fine.

So far nobody have been able to figure it out. any body know anything?

 

My best guess is there's a problem in the wiring between the alternator and the rest of the car. There is a voltage sense terminal that measures the battery voltage, and if it's not working correctly that might result in wrong charging voltage.

https://www.carparts.com/blog/altern...ring-diagrams/

 

Make sure the wires that go into the 2 prong plug aren't touching. A lot of cars have the sheathing deteriorated and the wires are touching. It's causing weird stuff to happen electrically. Following the diagram for the charging circuit doesn't leave many possibilities

 

cant figure it out, when it tests at the bench its fine, when i put it on my car its 18 volts as soon as i put the 12 volt wire on the connector, just a individual wire.

 

Thanks for the help, i have a regulator i. will try hooking it up. as soon as i put 12 volts to the alterrnator S terrminal, it goes to 18 but on the tester it puts out 14.