Correct, ammeter is OK. With batt disconnected ohm the black (downstream) lead to ground & if there is no draw it will read infinity & if there is a draw & there is, it'll show something. Downstream the black lead goes to the "welded splice" which is a T & it branches off to the (1) fuse box (2)st column ign switch (4) head ight switch (5) windshield wiper motor (6) horn relay) (7) out to alt (diodes). One of them is leaking juice. EDIT & that is ohming the black lead with it disconnected from ammeter