You can cause the alternator to draw current if you hook up the continuity tester backward, so a better way to check is with an ammeter in the circuit or by connecting the negative up on the battery and shunting a bulb between the + terminal and the + battery cable. If you are still drawing current, then yep, the alternator is bad. I just experienced that very thing on my sister's Mazda. The alternator charged ok, but also discharged. A rebuilt one fixed the problem. It is more likely a leaky diode than the regulator, but it is definately bad. I have run delco alternators with nothing but a sense wire (one wire congfiguration) on 2 vehicles now with no trouble. The bulb just lets the alternator come on sooner, by leaking some current to the regulator. It is supposed to be switched with the ignition anyway, so it is out of the circuit when the engine is off. Mine starts charging at 900 rpm, and then keeps charging when idling, so I don't worry about it.
