turn the key and the starter relay under hood hums everytime you try to start,has power but will not crank the starter
turn key and no start,starter was replaced with used one... on 1995 Dodge Caravan
What tune was the relay humming? I've only known relays that 'clicked',however low voltage (many possible causes)or a locked up engine have been known to make starters hum (usually just a low monotonous tune, no popular songs)..ON a more serious note(no pun intended)..Did you test the starter before installing it ? did you try to turn the motor manually(from flywheel or crank pulley end)?