On a 1981 Datsun 280ZX does anyone know the wiring hook up at the back of the altenator. I know there is a plug in connector and a connector to one buss terminal, but there is a third connector coming out of the wiring harness. I am assuming that is a ground. Does anyone know and if it is does it connect to the altenator or elsewhere? Thanks for your help. Note: The wire appears to be black and good sized.
You should have a field coil wire somewhere on there. It will come from
the voltage regulator - the regulator varies the voltage to the field coil
in the alternator, which in turn varies the voltage output of the
alternator. You may also have a stator wire, which will also go to the
I've never seen an alternator that had an actual ground wire, but your description of it being heavy kind of points to that.
Alternators that are not internally regulated typically have 3 wire connections, with the case typically being the ground. The 3 wires will then be the positive battery terminal, the field connection (labeled "F"), and many times the stator connection (labeled "S"), which is a connection for the regulator to sample the voltage.