Why wont my alternator charge

Lee Smith said
No but the newer alt should work on the older car and if I ground the the 65 alt it should work in the 85 Is that correct but back to my question I wasn't asking if I could use one alternator in the other vehicle and vises versa I was asking if it could be something else other than a voltage regulator that would cause the 65 dart TN not charge thanks for you time.

Yes, it could be a wiring problem. The voltage regulator could be fine and give your symptoms.

An 85 system has two field wires. The 65 does not. If it works in an 85 and not in a 65, you have the wrong alt.

A later model alt can be modified to work in a 65 though, or you can upgrade to the later model regulator and wiring which is what I would personally recommend since many alternators sold for the single wire field aren't compatible with your current setup and even new regulators can be difficult to source for the same reason.

An over charge condition can be caused by many things, not the least of which is poor wiring between the battery and your regulator or a bad ground.

You need to test to see how much field voltage/current is being sent through your regulator and whether the wiring from the battery to the regulator is any good. Also make sure all grounds are clean and show good continuity. That information can be used to determine the fault.

Or you can try a new regulator and hope when you rev it, your car doesn't catch fire before you shut it off. Your choice.