Big 3 upgrade: what is this connector on alternator?

[Mighty Buffalo]

Do I need it? I bought the kit from Marionbumper2bumper, and it's not discussed.

 

[gamefreakgc]

Let me look at mine in a little bit, I can't remember what my wires look like at the moment.

 

[thor999]

Check out the Alt upgrade threads I remember seeing many pics of this in them, ummm CSS144 alt upgrade?

 

[SIN-Japan]

Yes, that plug will need to remain connected.
The big 3 upgrade will only replace the main charging wire from the Alt to the Batt. as far as the Alt is concerned.

That plug should contain your Sense wire, Ignition wire and Alt light wire.