White plug under dash,right after ECU.

[leesredgt]

Im getting ready to drop my RB into my vert and i was just going to use the harness of my base model hatch b/c its already converted.So far everythig is pretty much the same,except this white plug under the dash.I know there is the brown plug the hooks up were the glove box is thats the only one i had to hook up the last time.The RB harness dosent have this white plug,so my question is do i need it?It sure was a pain in the butt to get to also.

Like i said my hatch was a base model so i dont know if that has anything to do with it.